The correct answer is D. RAM.
RAM (Random Access Memory) is a computer’s primary memory. It is a volatile memory, which means that it loses its contents when the computer is turned off. RAM is used to store data and instructions that the computer is currently using. It is much faster than the hard drive, which is why it is used to store the data that the computer is currently using.
Hard disk is a non-volatile storage device that stores data permanently. It is slower than RAM, but it can store much more data. Hard disk is used to store the operating system, programs, and files that the computer does not need to access immediately.
ROM (Read-Only Memory) is a type of memory that can only be read from. It is used to store the computer’s BIOS (Basic Input/Output System), which is a set of instructions that the computer uses to start up. ROM is also used to store some other important data, such as the computer’s serial number.
Floppy disk is a type of magnetic storage device that was once used to store data. It is now obsolete, having been replaced by newer technologies such as USB drives and CDs.