Explanation:

- RW (Rewritable):

- Used to denote optical discs that can be erased and recorded multiple times.

- Commonly found in formats like CD-RW and DVD-RW.

- Correct Answer.

- CD (Compact Disc):

- Optical disc primarily used for storing digital data.

- Mostly used for music and data storage, but not necessarily reusable.

- DVD (Digital Versatile Disc):

- Optical storage for larger capacities, mainly used for video and data.

- Can be once-write (DVD-R) or rewritable (DVD-RW).

- ROM (Read-Only Memory):

- Indicates data is written permanently; not reusable.

- Used in CDs, DVDs, and more.

- ROS (Read-Only Storage):

- Not a standard term for optical media.