What type of memory is Read-Only Memory (ROM)?

Read-Only Memory (ROM) is indeed best characterized as permanently stored data that is unchangeable, which is why option B is the correct answer. ROM is a type of non-volatile memory, meaning that it retains its contents even when the power is turned off. This permanent storage is crucial for holding firmware and system-critical information that must remain intact for the computer to function properly.

ROM is specifically designed to be read from but not written to in the same way that Random Access Memory (RAM) can be manipulated. It typically contains the instructions for booting the computer (the BIOS or firmware), making it foundational for the system’s operation. The unchangeable aspect means that while updates can be made through specific processes, the data is generally fixed, offering stability and reliability for essential operations.

The other options do not accurately describe the characteristics of ROM. Temporary and changeable memory would be indicative of RAM, while the notion that ROM is only used during boot-up narrows its function too much, as it can be accessed at other times as needed. Lastly, classifying ROM as a type of external storage is incorrect, as external storage refers to devices like USB drives or external hard drives, whereas ROM is integrated within the computer's hardware.