Which of the following are components of an “active” CPU cooling solution?

A.
A heatsink and thermal compound.

B.
A heatsink, radiator, and thermal compound.

C.
A heatsink, attached fan, and thermal compound.

D.
A heatsink, case fan, and thermal compound.

Explanation:

http://pcsupport.about.com/od/maintenance/tp/pc_cooling.htm