Amphibians are:

The correct option is B

cold-blooded and go into hibernation in winter.

An amphibian is a cold-blooded vertebrate that can survive in aquatic habitat and have gills to breathe in the dissolved oxygen. As they mature, they develop lungs, which help them to survive in the terrestrial habitat. Most of them hibernate during winter. Frogs, toads, and salamanders are classified as amphibians.