This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anitibody, Subject name: Microbiology
[{'content': 'First antibody to appear in intrauterine life \nSelect and explain. \nA. IgM, B. IgA, C. IgD, D. IgE', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) IgM', 'role': 'assistant'}]