Optical fiber works on the principle of total internal reflection.
The Total Internal Reflection is the phenomenon in which the complete reflection of a light ray reaching an interface with a less dense medium when the angle of incidence exceeds the critical angle.
“Interim” means in or for the intervening period; provisional. Options B and C are synonyms of the word and A and E are irrelevant. “Permanent” is the word which best explains the opposite meaning of “interim”. Thus, option D is the correct answer4
A magnetic disk is a storage device that uses a magnetization process to write, rewrite and access data. It is covered with a magnetic coating and stores data in the form of tracks, spots, and sectors. Hard disks, zip disks, and floppy disks are common examples of magnetic disks.
Hence, Magnetic disks are the most popular medium for both Direct access and Sequential access.