This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Types of vaccines, Subject name: Pediatrics
[{'content': 'Zero dose of polio vaccine is given at: \nSelect and explain. \nA. Before giving DPT, B. At bih, C. When child is having diarrhea, D. When child is having polio', 'role': 'user'}, {'content': 'Answer: B \nExplanation: - OPV zero dose: Given at bih / as early as possible within first 15 days of life. LATEST NATIONAL IMMUNIZATION SCHEDULE (NIS): 2019', 'role': 'assistant'}]