Final answer:
The operating system and other processes are protected from being modified by a running process by checking every address generated by the CPU against the relocation and limit registers.
Step-by-step explanation:
The correct answer is d) Every address generated by the CPU is being checked against the relocation and limit registers.
This is known as memory protection, which is a mechanism used by the operating system to ensure that each process can only access its assigned memory and doesn't interfere with other processes or the operating system itself.
The relocation register holds the starting address of the process in memory, while the limit register holds the size of the process's address space. Every memory access made by a process is checked against these registers to ensure that it stays within its allocated memory region.