This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
[{'content': 'The first cell culture vaccine was \nSelect and explain. \nA. Human diploid cell ( HDC ) vaccine, B. Low egg passage ( LEP ) vaccine, C. Purified chick embryo cell ( PCEC ) vaccine, D. Purified vero cell ( PVC ) vacccine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: An inactivated rabies vaccine for human use was first prepared in cell culture. It was shown that the human diploid cell (HDC) strain WI-38 was a suitable substrate for the propagation of the Pitman-Moore (PM) strain of fixed rabies virus. Ref : Ananthanarayana textbook of Microbiology 9th edition Pgno : 534', 'role': 'assistant'}]