Which one of the following structures in $Pheretima$ is correctly matched with its function?

The clitellum is the glandular band covering segments 14–16 of the mature earthworm; its gland cells secrete the cocoon in which the sperms and eggs are deposited and fertilisation takes place. This match is correct.
Setae are S-shaped structures in the body wall that help in locomotion, not defence.
The typhlosole is the internal median fold of the dorsal wall of the intestine that increases the effective area of absorption; it does not store nutrients.
The gizzard (segments 8–9) is muscular and grinds soil particles and decaying leaves; it does not absorb food.
Hence the correct match is clitellum – secretes cocoon.