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': 'Which antibody is most commonly produced in secondary immune response? \nSelect and explain. \nA. IgG, B. IgA, C. IgD, D. IgM', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) IgGRef: Jawetz 24/e, chapter 8', 'role': 'assistant'}]