The correct answer is A. RAM.
RAM (Random Access Memory) is a type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed without touching the preceding bytes. RAM is typically used to store data that is actively being used by a computer, such as the operating system, running programs, and open files.
ROM (Read-Only Memory) is a type of computer memory that is permanently stored on a chip. ROM is used to store data that does not need to be changed, such as the BIOS (Basic Input/Output System).
EPROM (Erasable Programmable Read-Only Memory) is a type of ROM that can be erased and reprogrammed. EPROM is used to store data that needs to be changed occasionally, such as the firmware for a device.
PROM (Programmable Read-Only Memory) is a type of ROM that can be programmed once. PROM is used to store data that needs to be changed very rarely, such as the calibration data for a device.
RAM is volatile memory, which means that it loses its contents when the power is turned off. ROM is non-volatile memory, which means that it retains its contents even when the power is turned off.