In Decode section of FDE, what happens?

• A. The instruction in the MDR is decoded by the CU; The CU then can prepare for the next step by loading the next MAR/MDR values.
• B. The next MAR/MDR values are loaded, ready for the following fetch.
• C. The instruction is executed immediately.
• D. The program counter is reset.

Answer: (B)

During the Decode phase, the fetched instruction is interpreted and the control signals needed to perform it are generated. In this design, decoding also sets up the next memory access by loading the next MAR and MDR values, so the following fetch can begin immediately. This preloading keeps the instruction stream moving smoothly. The actual execution happens in the Execute phase, not during decode; resetting the program counter isn’t part of decode, and simply executing the instruction wouldn’t align with this staged flow.