The dual mode operation of O/S is Pick ONE option

Dual mode operation (user mode and kernel/supervisor mode) is a fundamental OS protection mechanism that prevents user programs from directly accessing or corrupting the operating system and other processes. Option B and C refer to memory and I/O management features but are not the core purpose of dual mode operation.

Step-by-step Derivation:
Dual mode operation works by enforcing privilege levels: kernel mode allows unrestricted access to hardware and system resources, while user mode restricts access to privileged instructions and memory. This separation prevents a faulty or malicious user program from crashing the OS or interfering with other processes. Option A correctly identifies this protection mechanism, while options B and C describe separate OS features not directly related to dual mode's primary function.