Which of the following is used to execute a CPU instruction?

Correct Answer: Program Counter Explanation: The Program Counter (PC) stores the memory address of the next instruction to be fetched. The CPU uses the address in the PC to fetch the instruction from memory; after fetching, the CPU decodes and executes the instruction. The PC is then updated (usually incremented or changed by control-flow instructions) so it points to the following instruction. Role of the Program Counter: provides the address for the instruction fetch stage.

What executes instructions: the CPU's control unit and ALU perform decoding and execution once an instruction is fetched.

Why this option is best among the choices: other choices refer to protection mechanisms, computer type, or unrelated terms, not to the register that tracks instruction addresses.

Note: The Program Counter itself does not execute the instruction; it only points to where the next instruction is located. Execution is carried out by the CPU after the instruction is fetched.