ANS:B - CPU cycle

On the level of machine language, the operation of the CPU is fairly straightforward. The CPU executes a program that is stored as a sequence of machine language instructions in main memory.

It does this by repeatedly reading, or fetching, an instruction from memory and then carrying out, or executing, that instruction. This process -- fetch an instruction, execute it, fetch another instruction, execute it, and so on forever -- is called the fetch-and-execute cycle.