Which of the following could be the cause of this issue?

After installing a second processor and corresponding heatsink into a server, an administrator notices that the new processor is not showing up during POST. Which of the following could be the cause of this issue?

A.
The power supply is not sufficient to power the server.

B.
The voltage regulator module (VRM) was not installed.

C.
The IRQ setting was not set.

D.
The DMA setting was not set.