Select the option that is related to the third term in the same way as the second term is related to the first term:
$$\text{Butterfly : Insect :: Snake : ?}$$

This analogy maps an animal to its broader biological classification class or group.
* A Butterfly belongs to the biological class of Insect.
* Similarly, a Snake belongs to the biological class of Reptile.

Therefore, Reptile is the correct option.