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': 'Nervous tissue Rabies vaccines are usually manufactured from \nSelect and explain. \nA. Duck embryos, B. Human diploid cell, C. Sheep, D. Chick embryos', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]