ASemiconductor Memories
BMagnetic Disks
CMagnetic Tapes
DCompact Disks
Answer:
A. Semiconductor Memories
Read Explanation:
Semiconductor Memories is the correct answer.
Here is how they rank in terms of speed and access time (from fastest to slowest):
Semiconductor Memories (Fastest): Made of microelectronic circuits (silicon chips). This category includes RAM, ROM, and Cache memory. Their access times are measured in nanoseconds ($10^{-9}$ seconds).
Magnetic Disks: Such as traditional Hard Disk Drives (HDDs). Access times are measured in milliseconds ($10^{-3}$ seconds) due to moving mechanical parts (spinning platters and read/write heads).
Compact Disks (CDs): Optical storage devices that read data using laser beams. They are slower than magnetic disks.
Magnetic Tapes (Slowest): Sequential access media, meaning to reach data at the end of the tape, you must fast-forward through everything before it.
Semiconductor memory is dynamic/static electronic circuitry with zero mechanical movement, making it significantly faster than magnetic or optical storage.
