Which of the following will replace system binaries and/or hook into the function calls of the operating system to hide the presence of other programs (choose the most precise answer)?

A. rootkits

B. virus

C. trojan

D. tripwire

E. None of the choices.

Explanation:

-A backdoor may take the form of an installed program (e.g., Back Orifice) or could be in the form of an existing -legitimate- program, or executable file. A specific form of backdoors are rootkits, which replaces system binaries and/or hooks into the function calls of the operating system to hide the presence of other programs, users, services and open ports.-