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': 'Prognosis of a disease can be given by- \nSelect and explain. \nA. Secondary attack rate, B. Incubation period, C. Latency, D. Serial interval', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]