What type of memory retains its contents when the power is turned off?

Read-Only Memory (ROM) is a type of non-volatile memory, meaning it retains its stored data even when the power is turned off. This characteristic sets it apart from volatile memory types, such as Dynamic Random Access Memory (DRAM) and cache memory, which lose their contents when power is lost. ROM is often used to store firmware and essential system instructions that need to be preserved for the hardware to operate properly after being powered down. Therefore, the persistent nature of ROM makes it the correct answer to the question regarding memory that retains its contents without power.