How is thermal grease used when servicing HP computers?

A.
Thermal grease lubricates and cools connections in PCI and memory slots for installing new
components.

B.
Thermal grease must be applied between the system board and the processor to reduce heat
transfer.

C.
Thermal grease is applied between the processor and the heat sink upon replacement.

D.
Thermal grease cleans and lubricates cooling fans to increase efficiency and to decrease noise.

Explanation:

Reference:
http://en.wikipedia.org/wiki/Thermal_grease