Macro viruses usually infect Microsoft Office files and __________.

• A. install themselves when users click files
• B. delete all hard disk files on a specified date
• C. install themselves when the computer reboots
• D. None of the above

Answer: (A)

Macro viruses embed malicious code in Microsoft Office documents that runs when the user enables macros after opening the file. The typical infection occurs because users click to open or enable content in a document, allowing the macro to execute and then spread to other documents or locations. This behavior hinges on the need for user action to run the macro, which is why infection happens at the moment of opening or clicking the file. The other scenarios describe different malware patterns (a reboot-based trigger or a time/date trigger) that aren’t characteristic of how macro viruses spread.