The correct answer is: A. semiconductor memory
Semiconductor memory is a type of computer memory that uses semiconductor devices to store and retrieve data. It is the most common type of memory used in modern computers, and it is used for both primary and secondary storage.
Primary storage is the memory that is directly accessible by the CPU. It is used to store data that is currently being used by the CPU. Secondary storage is the memory that is used to store data that is not currently being used by the CPU. It is typically used to store programs and data that are not needed immediately.
Semiconductor memory is volatile, which means that it loses its contents when the power is turned off. This makes it unsuitable for storing data that needs to be preserved over time.
Magnetic tape, magnetic disk, and magnetic drum are all types of mass storage media. They are non-volatile, which means that they retain their contents even when the power is turned off. This makes them suitable for storing data that needs to be preserved over time.
Magnetic tape is a sequential access storage medium. This means that data can only be accessed in a linear fashion, from beginning to end. Magnetic disk is a random access storage medium. This means that data can be accessed in any order. Magnetic drum is a type of magnetic disk that is cylindrical in shape. It is typically used in mainframe computers.