The correct option is B Amphibian
An amphibian is any member of the group of vertebrate animals which are able to exploit both aquatic and terrestrial habitats, that is live both on land and in water. Hence, Option B is correct. Among the rest of the options, ambiguous means open to more than one interpretation; not having one obvious meaning, amorphous means without a clearly defined shape or form, ambivalent means having mixed feelings or contradictory ideas about something or someone. These do not express the intended meaning, hence incorrect.