The correct answer is C. main memory.
Main memory is a temporary storage area where the CPU can access data and instructions quickly. It is also known as RAM (random access memory). Main memory is volatile, which means that it loses its contents when the power is turned off.
ROM (read-only memory) is a type of memory that can only be read from, not written to. It is used to store permanent data and instructions, such as the BIOS (basic input/output system). ROM is non-volatile, which means that it retains its contents even when the power is turned off.
The control unit is a part of the CPU that controls the flow of data and instructions through the computer. It does not store data or instructions.
Coprocessor chips are specialized chips that can perform certain tasks more efficiently than the CPU. They are not used to store data or instructions.
E is not a valid option.