The correct option is A cocoon formation
The secretion of clitellum is highly active during the breeding season. It secretes a slimy substance that forms a girdle around the clitellum. This slimy substance later hardens to form the capsule called cocoon. The secretion of the accessory glands help the worms during copulation. Setae is responsible for the locomotion of earthworm. Nephridia is the excretory organ in earthworm. Digestion is performed by the help of the parts of the alimentary canal.