Solution

Clitellum is the ring-shaped, non-segmented glandular tissue or region in the body of annelids such as earthworm and leeches. It is a light coloured band that is present the earthworm instead of the 14$$^{th}$$, 15$$^{th}$$ and 16$$^{th}$$ segment in the body of an earthworm. It plays an important role in the process of copulation by secretion of mucus and cocoon for eggs. So, the correct answer is option B.