Which of the following best describes ROM?

The best description of ROM is that it is permanent storage that is non-volatile. ROM, or Read-Only Memory, is a type of memory used in computers and other devices that retains its contents even when the power is turned off, making it non-volatile. This characteristic distinguishes it from other types of memory that may lose data when power is lost.

ROM is primarily used to store firmware or software that is closely tied to the hardware, such as the BIOS in a computer system. Since the data in ROM is not meant to be modified frequently, it serves as a reliable means of preserving essential instructions required for the device to boot up and operate correctly. The permanence of this storage is crucial for maintaining the necessary startup processes, ensuring the device functions as intended each time it is powered on.

In contrast, options describing ROM as temporary storage, storage used for running applications, or cache memory do not accurately capture the essential nature and primary functions of ROM.