Pearl oyster belong to the class:

Correct option is A

Correct Answer: (a) Bivalvia
Explanation:
→ Pearl oysters (genus Pinctada and others) are bivalve molluscs — two-valved shelled animals in Class Bivalvia.
→ They secrete nacre (mother-of-pearl) that forms pearls around irritants or implanted nuclei.
Information Booster:
→ Bivalvia includes clams, oysters, mussels — all economically important shellfish.
Additional Information (Other Options):
(b) Gastropods: snails; (c) Cephalopods: octopus/squid; (d) Polyplacophora: chitons — different molluscan classes.