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': 'The commonest Ig G with maximum individual variation is - \nSelect and explain. \nA. IgG 1, B. IgG 2, C. IgG 3, D. IgG 4', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]