Explanation:
Warchalking is the drawing of symbols in public places to advertise an open Wi-Fi wireless network. Having found a Wi-Fi node, the warchalker draws a special symbol on a nearby object, such as a wall, the pavement, or a lamp post. The name warchalking is derived from the cracker terms war dialing and war driving.
Answer option B is incorrect. War driving, also called access point mapping, is the act of locating and possibly exploiting connections to wireless local area networks while driving around a city or elsewhere. To do war driving, one needs a vehicle, a computer (which can be a laptop), a wireless Ethernet card set to work in promiscuous mode, and some kind of an antenna which can be mounted on top of or positioned inside the car. Because a wireless LAN may have a range that extends beyond an office building, an outside user may be able to intrude into the network, obtain a free Internet connection, and possibly gain access to company records and other resources.
Answer option C is incorrect. War dialing is a technique of using a modem to automatically scan a list of telephone numbers, usually dialing every number in a local area code to search for computers, BBS systems, and fax machines. Hackers use the resulting lists for various purposes, hobbyists for exploration, and crackers (hackers that specialize in computer security) for password guessing.
Answer option A is incorrect. Spamming is the technique of flooding the Internet with a number of copies of the same message. The most widely recognized form of spams are e-mail spam, instant messaging spam, Usenet newsgroup spam, Web search engine spam, spam in blogs, online classified ads spam, mobile phone messaging spam, Internet forum spam, junk fax transmissions, social networking spam, television advertising and file sharing network spam.