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': 'Which of the following is primary cell line ? \nSelect and explain. \nA. Chick embryo fibroblast, B. Hela cells, C. Vero cells, D. WI-38', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Chick embryo fibroblast Chick embryo fibroblast is primary cell culture.", 'role': 'assistant'}]