Answer: Option D
Magnetic storage devices: These are devices that store data using magnetic patterns. The data is written onto the magnetic surface in the form of tiny magnetized regions that can be read by the device's read/write head. The strength and polarity of the magnetic field determine the values of the binary data. There are two types of magnetic storage devices, namely, hard disk drives (HDD) and magnetic tape storage.
Let's understand how each of the given options uses magnetic storage:
A. Hard Disk: A hard disk is a primary storage device that uses magnetic storage to store and retrieve digital information using one or more rigid rapidly rotating disks (platters) coated with magnetic material. Hard disks use read-write heads to read and write data on the spinning platters. The read/write head accesses the data by sensing the changes in the magnetic field caused by the magnetized regions.
B. Compact Disk: A compact disk (CD) uses optical storage to store digital data, but the process of writing the data onto a CD involves a magnetic process. The CD writer uses a laser to burn pits onto the surface of the disk, which can be read by a CD player. These pits are created by heating the disk's surface with a laser, which magnetizes the disk's surface in a specific pattern.
C. Audio Tapes: Audio tapes are also an example of magnetic storage devices. They use a thin plastic strip coated with a magnetic material that records audio signals onto the tape. The tape is passed through a magnetic head, which reads the magnetized regions on the tape and converts them into audio signals.
In conclusion, all of the given options (hard disk, compact disk, and audio tapes) are magnetic storage devices, as they all use magnetic patterns to store and retrieve digital information.