The machine cycle consists of which four steps?

• A. Fetch, Decode, Execute, and Store
• B. Input, Process, Output, and Storage
• C. Read, Write, Execute, Terminate
• D. Fetch, Execute, Decode, Store

Answer: (A)

The machine cycle is built around a simple flow: fetch an instruction, decode what it means, execute the required operation, and then store the result. First, the CPU pulls the next instruction from memory using the program counter and places it in the instruction register. Next, it decodes that instruction to determine the operation and identify which operands are involved. Then it carries out the operation—such as performing arithmetic, moving data, or interacting with memory or I/O. Finally, it stores the outcome in the appropriate place, like a register or memory, and prepares to fetch the next instruction.

This order is essential because you must know what to do (decode) before you can perform it (execute), and only after the operation is done can you save the result (store). The other sequences don’t fit: a model of data flow like Input/Process/Output/Storage describes overall processing, not the CPU’s instruction-handling steps; a sequence like Read/Write/Execute/Terminate isn’t a standard four-step cycle and includes an uncommon termination step; and performing before decoding (Fetch, Execute, Decode, Store) would mean attempting to run instructions without understanding them first.