This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other Key Definitions & Concepts, Subject name: Social & Preventive Medicine
[{'content': 'Generation time in epidemiology is defined as: \nSelect and explain. \nA. The interval between marriage and the bih of first child, B. The interval of time between the receipt of infection by host and maximal infectivity of the host, C. The interval of time between primary case and secondary cases, D. Interval of time between invasion by infectious agent and appearance of first sign or symptom of the disease/ in question', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Generation time: Time gap between entry of organism till its maximum infectivity. It is roughly equal to IP of the disease. OTHER DEFINITIONS: Incubation period: Time interval between invasion by an infectious agent & appearance of first sign or symptom of disease. Median Incubation period :Time required for 50% of cases to occur following exposure. Serial interval: Interval between primary & secondary case.', 'role': 'assistant'}]