The correct option is C Osphradium
Pila globosa is an amphibious apple snail found in the Indian subcontinent. An osphradium is a chemoreceptor and it is located near the left nuchal opening of Pila. Osphradium is attached to the mantle and is made of a central axis and 22-28 fleshy leaflets that carry chemoreceptors. So, the correct answer is option C.