In the context of Indian wildlife, the flying fox is a

Answer: (a) Bat

The flying fox is a large fruit bat — it looks fox-faced.

The idea

The Indian flying fox is one of the largest bats in the world, with a wingspan of over a metre and a long, fox-like face. It eats fruit and nectar and roosts by day in noisy colonies on big trees.

Flying fox → a bat → Sea horse → a fish → Silverfish → an insect → Starfish and jellyfish → not fish → Sea cow (dugong) → a mammal

Also know

Large flying foxes find food by sight and smell and do not echolocate; Rousettus fruit bats do, with tongue clicks.