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': 'Chikungunya is caused by ? \nSelect and explain. \nA. Mosquito-borne Alphavirus, B. Mosquito-borne Beta virus, C. Mosquito-borne Gamma virus, D. Mosquito-borne Deltavirus', 'role': 'user'}, {'content': "Answer: A \nExplanation: Chikungunya caused by a mosquito-borne alphavirus.Previous outbreaks had been confined to the tropics, and some have attributed this expansion to global warming. Ref: Harrison's Principles of Internal Medicine, 18e, Chapter 119.Introduction to Infectious Diseases.", 'role': 'assistant'}]