Free NCA-GENL Exam Braindumps
Generative AI LLMs Questions 41–45 (page: 10)

Updated On: 10-Feb-2026

When designing prompts for a large language model to perform a complex reasoning task, such as solving a multi-step mathematical problem, which advanced prompt engineering technique is most effective in ensuring robust performance across diverse inputs?

  1. Zero-shot prompting with a generic task description.
  2. Few-shot prompting with randomly selected examples.
  3. Chain-of-thought prompting with step-by-step reasoning examples.
  4. Retrieval-augmented generation with external mathematical databases.

Answer(s): C

Explanation:

Chain-of-thought (CoT) prompting is an advanced prompt engineering technique that significantly enhances a large language model's (LLM) performance on complex reasoning tasks, such as multi-

step mathematical problems. By including examples that explicitly demonstrate step-by-step reasoning in the prompt, CoT guides the model to break down the problem into intermediate steps, improving accuracy and robustness. NVIDIA's NeMo documentation on prompt engineering highlights CoT as a powerful method for tasks requiring logical or sequential reasoning, as it leverages the model's ability to mimic structured problem-solving. Research by Wei et al. (2022) demonstrates that CoT outperforms other methods for mathematical reasoning. Option A (zero-shot) is less effective for complex tasks due to lack of guidance. Option B (few-shot with random examples) is suboptimal without structured reasoning. Option D (RAG) is useful for factual queries but less relevant for pure reasoning tasks.


Reference:

NVIDIA NeMo Documentation: https://docs.nvidia.com/deeplearning/nemo/user- guide/docs/en/stable/nlp/intro.html
Wei, J., et al. (2022). "Chain-of-Thought Prompting Elicits Reasoning in Large Language Models."



In the development of trustworthy AI systems, what is the primary purpose of implementing red- teaming exercises during the alignment process of large language models?

  1. To optimize the model's inference speed for production deployment.
  2. To identify and mitigate potential biases, safety risks, and harmful outputs.
  3. To increase the model's parameter count for better performance.
  4. To automate the collection of training data for fine-tuning.

Answer(s): B

Explanation:

Red-teaming exercises involve systematically testing a large language model (LLM) by probing it with adversarial or challenging inputs to uncover vulnerabilities, such as biases, unsafe responses, or harmful outputs. NVIDIA's Trustworthy AI framework emphasizes red-teaming as a critical step in the alignment process to ensure LLMs adhere to ethical standards and societal values. By simulating worst-case scenarios, red-teaming helps developers identify and mitigate risks, such as generating toxic content or reinforcing stereotypes, before deployment. Option A is incorrect, as red-teaming focuses on safety, not speed. Option C is false, as it does not involve model size. Option D is wrong, as red-teaming is about evaluation, not data collection.


Reference:

NVIDIA Trustworthy AI: https://www.nvidia.com/en-us/ai-data-science/trustworthy-ai/



When using NVIDIA RAPIDS to accelerate data preprocessing for an LLM fine-tuning pipeline, which specific feature of RAPIDS cuDF enables faster data manipulation compared to traditional CPU-based Pandas?

  1. Automatic parallelization of Python code across CPU cores.
  2. GPU-accelerated columnar data processing with zero-copy memory access.
  3. Integration with cloud-based storage for distributed data access.
  4. Conversion of Pandas DataFrames to SQL tables for faster querying.

Answer(s): B

Explanation:

NVIDIA RAPIDS cuDF is a GPU-accelerated library that mimics Pandas' API but performs data manipulation on GPUs, significantly speeding up preprocessing tasks for LLM fine-tuning. The key feature enabling this performance is GPU-accelerated columnar data processing with zero-copy memory access, which allows cuDF to leverage the parallel processing power of GPUs and avoid unnecessary data transfers between CPU and GPU memory. According to NVIDIA's RAPIDS documentation, cuDF's columnar format and CUDA-based operations enable orders-of-magnitude faster data operations (e.g., filtering, grouping) compared to CPU-based Pandas. Option A is incorrect, as cuDF uses GPUs, not CPUs. Option C is false, as cloud integration is not a core cuDF feature. Option D is wrong, as cuDF does not rely on SQL tables.


Reference:

NVIDIA RAPIDS Documentation: https://rapids.ai/



In the context of evaluating a fine-tuned LLM for a text classification task, which experimental design technique ensures robust performance estimation when dealing with imbalanced datasets?

  1. Single hold-out validation with a fixed test set.
  2. Stratified k-fold cross-validation.
  3. Bootstrapping with random sampling.
  4. Grid search for hyperparameter tuning.

Answer(s): B

Explanation:

Stratified k-fold cross-validation is a robust experimental design technique for evaluating machine learning models, especially on imbalanced datasets. It divides the dataset into k folds while preserving the class distribution in each fold, ensuring that the model is evaluated on representative samples of all classes. NVIDIA's NeMo documentation on model evaluation recommends stratified cross-validation for tasks like text classification to obtain reliable performance estimates, particularly when classes are unevenly distributed (e.g., in sentiment analysis with few negative samples). Option A (single hold-out) is less robust, as it may not capture class imbalance. Option C (bootstrapping) introduces variability and is less suitable for imbalanced data. Option D (grid search) is for hyperparameter tuning, not performance estimation.


Reference:

NVIDIA NeMo Documentation: https://docs.nvidia.com/deeplearning/nemo/user-
guide/docs/en/stable/nlp/model_finetuning.html



When preprocessing text data for an LLM fine-tuning task, why is it critical to apply subword tokenization (e.g., Byte-Pair Encoding) instead of word-based tokenization for handling rare or out- of-vocabulary words?

  1. Subword tokenization reduces the model's computational complexity by eliminating embeddings.
  2. Subword tokenization creates a fixed-size vocabulary to prevent memory overflow.
  3. Subword tokenization breaks words into smaller units, enabling the model to generalize to unseen words.
  4. Subword tokenization removes punctuation and special characters to simplify text input.

Answer(s): C

Explanation:

Subword tokenization, such as Byte-Pair Encoding (BPE) or WordPiece, is critical for preprocessing text data in LLM fine-tuning because it breaks words into smaller units (subwords), enabling the model to handle rare or out-of-vocabulary (OOV) words effectively. NVIDIA's NeMo documentation on tokenization explains that subword tokenization creates a vocabulary of frequent subword units, allowing the model to represent unseen words by combining known subwords (e.g., "unseen" as "un" + "##seen"). This improves generalization compared to word-based tokenization, which struggles with OOV words. Option A is incorrect, as tokenization does not eliminate embeddings. Option B is false, as vocabulary size is not fixed but optimized. Option D is wrong, as punctuation handling is a separate preprocessing step.


Reference:

NVIDIA NeMo Documentation: https://docs.nvidia.com/deeplearning/nemo/user- guide/docs/en/stable/nlp/intro.html



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