What type of attack changes its signature and/or payload to avoid detection by antivirus programs?

What type of attack changes its signature and/or payload to avoid detection by antivirus programs?

A.
Polymorphic

B.
Rootkit

C.
Boot sector

D.
File infecting

Explanation:
In computer terminology, polymorphic code is code that mutates while keeping the original algorithm intact. This technique is sometimes used by computer viruses, shellcodes and computer worms to hide their presence.