What is the primary function of the CPU in a computer system?

• A. Executes instructions and coordinates the activities of all other components.
• B. Manages hardware resources and runs applications.
• C. Stores data long-term on disk.
• D. Handles user input from peripherals.

Answer: (A)

The CPU’s main job is to act as the brain of the computer: it executes instructions from programs and coordinates the activities of all other components. It does this by continually performing the fetch-decode-execute cycle, where it grabs an instruction from memory, interprets what it means, and carries out the required operation—whether that’s performing calculations, moving data, or controlling the flow of information between memory and peripherals. Through its control unit, the CPU sends the right signals to memory, storage, and I/O devices so everything works in harmony to complete tasks.

The other descriptions point to roles that belong to other parts of the system: managing hardware resources and running applications describes the operating system's job; storing data long-term on disk is the function of storage hardware; handling user input from peripherals is handled by input devices and the software that processes that data. The CPU is essential for performing those operations, but its primary function is to execute instructions and coordinate system activity.