Which type of memory is non-volatile and retains data without power?

The correct choice is ROM (Read-Only Memory). This type of memory is designed to be non-volatile, meaning it retains its stored data even when the power is turned off. ROM is commonly used to store firmware, which is the essential software that controls hardware at a basic level during the computer's boot process. Unlike RAM (Random Access Memory), which is volatile and loses its data when power is lost, ROM provides critical information that the system needs to start and operate.

Cache memory and virtual memory serve different purposes. Cache memory is high-speed storage that temporarily holds data currently being processed, but it is also volatile and loses its data when power is cut. Virtual memory involves using a portion of the hard drive to simulate additional RAM, and is primarily a management technique for running more applications than would fit in the physical RAM. Both cache memory and virtual memory do not retain data without power, aligning them as options that do not meet the criteria of being non-volatile.