Which memory type retains data even when the power is off?

The type of memory that retains data even when the power is off is Read-Only Memory (ROM). This non-volatile memory is specifically designed to hold data that should not be lost when the computer is turned off. ROM is used to store firmware or software that is closely tied to the hardware, such as the system's BIOS.

In contrast, RAM, cache memory, and volatile memory all lose their data when the power is cut off. These types of memory are designed for temporary data storage to allow for fast access while the device is powered on, supporting applications and processes that require quick read and write capabilities. This distinction makes ROM essential for maintaining critical instructions needed for booting and running hardware, even without power.