Which of the following is solely designed to avoid detection by an antivirus program by using the un

Which of the following is solely designed to avoid detection by an antivirus program by using the
underlying operating system to its advantage?

A.
Rootkit

B.
Virus

C.
Trojan

D.
Worm

Explanation:
http://www.webopedia.com/TERM/R/rootkit.html