Under the usual personal-computer component convention, where CMOS memory…

Concept

Volatility describes whether stored information survives when power is no longer supplied. A memory cell and the complete computer component that contains it can be classified differently when the component has an independent backup power source.

SRAM and DRAM cells need continuous power; flash cells and magnetic disks retain state without it. In PC terminology, CMOS memory usually means the battery-backed RTC/BIOS configuration store, so examination keys commonly treat the component as non-volatile even though its underlying SRAM cell is intrinsically volatile.

Application:

• CMOS memory (A): the SRAM cell needs power, but the motherboard coin-cell continues supplying it after the computer is switched off; under the component-level convention used here, the stored configuration is retained.

• Cache memory (B): CPU cache is ordinarily SRAM without an independent backup supply, so its contents disappear when system power is removed.

• Flash memory (C): floating-gate storage retains charge without continuous power, so its data persists after shutdown.

• Hard disk (D): magnetic domains on the platter retain their orientation without electrical power.

• RAM (E): ordinary main memory needs continuous power (and DRAM needs refresh), so its contents disappear after shutdown.

Cross-check and contrast

Switching off the computer removes normal system power from cache and RAM, but flash and hard-disk data remain, while the CMOS configuration continues to receive backup power from the coin-cell. Therefore the volatile components in the exam’s system-level convention are Cache memory (B) and RAM (E), giving “(B) and (E) only.”

The learner’s doubt is valid at the cell level: if both the main supply and CMOS battery are removed, the SRAM-based CMOS store loses its contents. The saved key uses the conventional PC-component classification, not the isolated-cell classification.