Back Orifice is an example of:

A.
a virus.

B.
a legitimate remote control software.

C.
a backdoor that takes the form of an installed program.

D.
an eavedropper.

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.