This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'Time period between primary case and secondary case is known as? \nSelect and explain. \nA. Generation time, B. Serial interval, C. Secondary attack rate, D. Incubation period', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Serial interval.", 'role': 'assistant'}]