Answer: Option A
The machine cycle is the basic operation performed by a computer's central processing unit (CPU). It involves fetching an instruction from memory, decoding the instruction, executing it, and storing the result. The control unit is responsible for controlling the machine cycle.
Here are some relevant definitions and formulas related to the control unit:

• Control Unit: The control unit is a component of the CPU that manages the machine cycle. It retrieves instructions from memory and decodes them, determining which operations the computer needs to perform.
• Fetch: The fetch stage of the machine cycle involves retrieving an instruction from memory.
• Decode: The decode stage of the machine cycle involves interpreting the instruction and determining which operations to perform.
• Execute: The execute stage of the machine cycle involves carrying out the operations specified by the instruction.
• Store: The store stage of the machine cycle involves saving the results of the operation back to memory or registers.
• Clock Cycle: The clock cycle is the amount of time it takes for the CPU to complete one machine cycle. It is measured in Hertz (Hz).
• Instruction Register (IR): The IR is a register in the CPU that stores the current instruction being executed.
• Program Counter (PC): The PC is a register in the CPU that stores the memory address of the next instruction to be executed.

The control unit is responsible for coordinating the various stages of the machine cycle. It retrieves instructions from memory, decodes them, and determines which operations the computer needs to perform. It then sends signals to the appropriate parts of the CPU to carry out the necessary operations.
In conclusion, the correct answer to the question is A. Control unit, as it is the component of the CPU that controls the machine cycle by coordinating the fetch, decode, execute, and store stages.