Answer: A) Memory Explanation: In a computer, the area where the data is stored for the quick access by the computer's processor is called Main storage or Primary storage or Memory or RAM.   Hence, main storage is also called Memory.

Answer: C) Both A & B Explanation: Secondary storage therefore needed because it is non-volatile, meaning it retains its contents without the need for a power supply. It also has the large storage capacity needed to store the operating system and all the programs and files needed by a modern computer system.

Answer: D) All the above Explanation: An operating system has three main functions: (1) manage the computer's resources, such as the central processing unit, memory, disk drives, and printers, (2) establish a user interface, and (3) execute and provide services for applications software.