Answer:
c. Larval urochordates and adult cephalochordates
Step-by-step explanation:
A chordate is an animal which has all these following characters at any stage of embryonic development:
(1) a notochord
(2) a dorsal hollow nerve cord,
(3) pharyngeal gill slits
(4) a tail.
Cephalochordates are a class of marine animals which retain all these 4 characteristics even in adult stage while in other animals some of these characters disappear during embryonic development. Urochordates have all these four characters only till larval stage but during embryonic development some of these characters disappear so an adult urochordate will have only few of these characters.