Which of the following is a common role of the Memory Address Register (MAR) in the fetch step?

• A. Stores the data to be written to memory
• B. Holds the program counter value
• C. Holds the address to be accessed in memory during the fetch
• D. Holds the instruction after fetch

Answer: (C)

During the fetch step, the processor must specify which memory location to read from. The Memory Address Register holds that exact address, guiding the memory unit to the correct location. Typically, the next instruction address comes from the program counter and is loaded into the MAR so the system knows which word to fetch. The memory then places the retrieved instruction onto the data path, usually transferring it to the Memory Data Register and from there into the Instruction Register for decoding. This makes the MAR’s role clear: it stores the address to be accessed during the fetch. The other options describe different registers or functions (data to write is held by the MDR, the program counter itself isn’t the MAR, and the fetched instruction resides in the IR, not the MAR).