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: Microbiology
[{'content': 'Pocks on chick embryo are formed by all except \nSelect and explain. \nA. Variola, B. Vaccinia, C. Chickenpox, D. Cowpox', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Chicken Pox", 'role': 'assistant'}]