When a computer fetches an instruction, the binary code representing the instruction appears on the: A. I/O address bus B. memory data bus C. input data bus D. output data bus E. None of the above

The correct answer is: B. memory data bus

The memory data bus is a set of lines that carry data between the CPU and memory. When a computer fetches an instruction, the binary code representing the instruction is read from memory and placed on the memory data bus. The CPU then reads the instruction from the memory data bus and executes it.

The I/O address bus is a set of lines that carry addresses of I/O devices to the CPU. The CPU uses the I/O address bus to access I/O devices.

The input data bus is a set of lines that carry data from input devices to the CPU. The CPU uses the input data bus to read data from input devices.

The output data bus is a set of lines that carry data from the CPU to output devices. The CPU uses the output data bus to write data to output devices.

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