Files exist on storage devices, such as hard disks, dvds, usb drives, and reels of magnetic tape.

Files exist on data storage devices, such as hard disks, DVDs, USB drives, and reels of magnetic tape.
Data storage is the recording (storing) of information (data) and these data storage devices use a technology consisting of computer components and recording media used to retain digital data.DVDs, USBs and hard disks are examples for external data storage devices.

Answer (a) with a mirror like surface;