Assertion: Branchiostoma and Balanoglossus are bilaterally symmetrical and triploblastic animals.
Reason: They are exclusively marine and possess notochord.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
C.
If assertion is true but reason is false.
Balanoglossus (Phylum-Hemichordata) and Branchiostoma (= Amphioxus, Subphylum - Cephalochordata) both are bilaterally symmetrical and triploblastic animals. Both are marine animals. Balanoglossus does not possess a notochord whereas Branchiostoma being a chordate possesses notochord that persists throughout life.