A virus that infects an application program is known as a _________.

a) boot sector virus
b) macro virus
c) Trojan horse
d) file virus

From what I understand, both macro viruses and file viruses affect application programs such as Word and Excel. So which is the right answer?

The correct answer is b) macro virus.

A macro virus is a type of virus that infects application programs, particularly those that use macros, such as Microsoft Word or Excel. These viruses exploit the macro programming language within the application to spread and execute their malicious code.

To arrive at this answer, you need to understand the different types of viruses that exist. Here's a brief explanation of the other options:

a) Boot sector virus: This type of virus infects the boot sector of a storage device, like a hard drive or a USB drive. It usually spreads when the infected device is booted or accessed. While it can cause harm to an application program indirectly, it is not the specific type of virus that primarily targets application programs.

c) Trojan horse: A Trojan horse is a malicious program disguised as legitimate software. It tricks users into executing it, often by pretending to be a useful application or by piggybacking on a trusted program. Unlike a macro virus, which infects application programs directly, a Trojan horse infects a system by fooling the user into running it.

d) File virus: This is a more general term that refers to any virus that infects files. File viruses can infect various types of files, including system files, executable files, and other document files. Though they can also infect application programs, they are not specialized in targeting macros within those programs.