Answer:
C. Hard disk drive.
Step-by-step explanation:
The computer system is an electronic device that uses its hardware and software components to process input data. The hardware components are divided into input unit, output unit, memory unit and processing unit.
The memory unit are to different types, they are the main memory and the primary storage. The main memories are the read only memory (ROM) and the random access memory (RAM).
The primary storage like the hard disk drive (HDD) and the solid state drive(SSD) are used to hold and run the operating system used to manage the system. There are secondary storages that are used to store data outside a computer.