Andrew has a personal computer. One morning, he starts his computer and finds the following error
message:
“CMOS checksum failure.”
What are the most likely causes of this error?
Each correct answer represents a complete solution. Choose two.

A.
The CMOS battery has failed.

B.
BIOS has become outdated.

C.
The CMOS chip has failed.

D.
Software stored in the CMOS battery is infected by a virus.