Explanation:

'System software' is the category of software responsible for managing and controlling the computer's hardware components and providing a platform for application software to run. This includes operating systems, device drivers, and utility programs. 'Application software' is designed for specific user tasks (e.g., word processors, web browsers). A 'program' is a general term for a set of instructions, which can be either system or application software. 'Memory' is a hardware component, not a type of software. Therefore, system software is the correct answer as it directly controls the hardware.