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: Medicine
[{'content': 'Which one of the following diseases has lowest incubation period \nSelect and explain. \nA. Small pox, B. Diphtheria, C. Cholera, D. Dengue', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Small pox - 7-14 days\nDiphtheria - 2-6 days\nCholera - 1-2 days\nDengue - 3-10 days.', 'role': 'assistant'}]