The CPU frequency is also called the clock frequency, the unit is megahertz (MHz) or gigahertz (GHz2), its role is:

The CPU frequency is also called the clock frequency, the unit is megahertz (MHz) or gigahertz (GHz2), its role is:
A . Used to indicate the speed of CPU calculation and data processing
B . Determine the transmission speed of bus data
C . Determine the running speed of the whole mainboard
D . Determine the speed of data exchange between CPU and memory

Answer: A