Which of the following best describes Read Only Memory (ROM)?

Read Only Memory (ROM) is best described as permanent memory that is not meant to be altered. This characteristic is fundamental to the purpose of ROM, which is to store firmware or software that is critical to the system's operation, such as the BIOS in personal computers.

ROM retains its contents even when the power is turned off, distinguishing it from volatile memory types, which lose data when power is lost. This immutability is crucial for the reliable functioning of devices, as it ensures that essential instructions for booting up and system integrity are preserved. The design of ROM allows it to be used in various applications where fixed data is necessary, and attempts to rewrite this memory are usually either not possible or can compromise the data it stores.

In contrast, options that describe memory as easily rewritten, volatile, or temporary storage are misaligned with the fundamental characteristics of ROM. Each of these alternatives highlights traits more appropriate for other memory types, such as Random Access Memory (RAM) or cache memory, which are designed to be flexible and frequently updated.