Which type of RAM is considered non-volatile?

Non-volatile memory retains its data even when the power is turned off. ROM (Read-Only Memory) is a prime example of non-volatile memory, as it is specifically designed to store firmware or software that does not change frequently. This characteristic makes it suitable for storing the system's BIOS or boot instructions, which need to be available immediately upon startup, regardless of whether the computer is powered on or off.

In the context of RAM types, SRAM (Static RAM) and DRAM (Dynamic RAM) are both considered volatile memory. They lose all stored data when power is lost. Flash memory, while also non-volatile, is not classified as RAM; instead, it falls under different types of storage technologies, often used for things like USB drives and SSDs. Therefore, ROM is the clear answer to the question regarding non-volatile types of memory.