Explanation:

The **Motherboard** is the central printed circuit board that connects and allows communication between all crucial electronic components of a computer system, including the CPU, memory, and peripheral devices. It provides the electrical pathways (buses) for data exchange, effectively controlling overall system communication. * **Option A (ALU):** The ALU (Arithmetic Logic Unit) performs arithmetic and logical operations within the CPU; it does not control overall system communication. * **Option B (Semiconductor):** A semiconductor is a material used in electronic components, not a component itself that controls communication. * **Option C (Motherboard):** This is the correct answer. The motherboard acts as the central hub for all internal communication. * **Option D (Coprocessor):** A coprocessor is a specialized processor that assists the main CPU with specific tasks, but it does not control general system communication.