Choice "C" is correct, which means that both "d" and "b" are incorrect. Choice "a" is incorrect. A virus is a piece of computer program that inserts itself into some other program. Virus protection software can be utilized to protect against viruses. One of the benefits of such software is definitely not that it can be installed and forgotten. Virus protection software must be continually updated because new viruses are being continually developed. Security personnel who install and forget virus protection software will soon be looking for new jobs. Choice "d" is the incorrect choice because it is not the only correct answer. A denial-of-service attack is an attack in which one computer bombards another computer with a flood of information intended to keep legitimate users from accessing the target computer or network.Choice "b" is the incorrect choice because it is not the only correct answer. Phishing is the sending of phony emails to try to convince people to divulge information like account numbers and social security numbers. It is often accomplished by luring people to authentic-looking but fake websites.