This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunization, Subject name: Pediatrics
[{'content': 'OPV Bivalent vaccine contain: \nSelect and explain. \nA. P1 & P2, B. PI & P3, C. P2 & P3, D. P1, P2 & P3', 'role': 'user'}, {'content': "Answer: B \nExplanation: b. P1 & P3(Ref: Nelson's 20/e p 1561, 3212, Ghai 8/e p 190-194)Monovalent OPVs (mOPVs) & bivalent OPV (bOPV) are 2.5-3 times more efficacious than trivalent OPVIn bivalent OPV, the type 2 component is removed", 'role': 'assistant'}]