Comprehensive and Detailed Explanation From CEH v13 Guide Topics:

The correct answer is D. Multipartite Virus. A multipartite virus is a sophisticated type of malware that infects multiple parts of a computer system simultaneously, most commonly the boot sector and executable files. Because it attacks more than one target, it can spread rapidly and is often more difficult to remove than single-vector viruses. Even if infected executable files are cleaned, the virus may remain active in the boot sector and reinfect the system during startup. Likewise, cleaning only the boot sector may leave infected files that can later reinfect the boot area.

Option A (Stealth Virus) is designed to hide its presence by manipulating operating system functions and returning false information to security tools. Option B (Polymorphic Virus) changes its code or signature each time it infects a system to evade detection by antivirus software. Option C (Macro Virus) primarily infects documents and applications that support macro languages, such as Microsoft Office files.

From a CEH malware analysis perspective, malware is often classified by its infection method, propagation technique, and concealment strategy. The defining characteristic of a multipartite virus is its ability to infect both the boot sector and executable files simultaneously, making D the correct answer.