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': 'An important measure of the communicability of a disease is - \nSelect and explain. \nA. Case fatality rate, B. Disease specific mortality rate, C. Infection rate, D. Secondary attack rate', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]