What could be the reason why a 1 GHz laptop is operating at 700 MHz?

What could be the reason why a 1 GHz laptop is operating at 700 MHz?

A.
The laptop is making use of CPU throttling technology.

B.
The laptop does not have overclocking enabled.

C.
The laptop will require additional memory to operate at full potential.

D.
The laptop is installed with an incorrect processor.