Explanation:

CD-ROM (Compact Disc Read-Only Memory) is an optical memory, not semiconductor or magnetic memory.

• Semiconductor memory includes RAM and ROM chips.
• Magnetic memory includes hard disks and floppy disks.
• CD-ROM uses a laser to read data stored as tiny pits on the surface of the disc, which is why it's categorized as optical memory.

So, option (D) is correct because none of the other options accurately describe CD-ROM.