Final answer:
Physical memory is divided into fixed-sized blocks called frames. The answer a) Frames is correct. Pages and backing store are related concepts but refer to virtual memory management and non-volatile storage respectively.
Step-by-step explanation:
Physical memory is broken into fixed-sized blocks called frames. The correct answer to the question is a) Frames. Memory management in operating systems uses this concept to manage how processes are mapped into physical memory.
A page is a similar concept but refers to the way an operating system manages the virtual memory space of a process, and these pages are loaded into frames when they are brought into physical memory. The backing store, usually a hard drive or other non-volatile storage, is where pages are stored when they are not currently held in physical memory.