Answer: 3. Larval urochordates and adult cephalochordates
Urochordata and Cephalochordata are the two subphylums of Chordata. Urochordata are living organisms that have a notochord present in the posterior part of their body that forms a tail at their larval stage. Cephalochordata are living organisms that have a notochord extending to the exterior parts of their body. This often occurs in the post-larval stages of their lives.
Therefore, the third option, “Larval urochordates and adult cephalochordates” best Answers the question above.