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': 'If a patient were genetically unable to make J chains, which immunoglobulins would be affected? \nSelect and explain. \nA. IgG and IgA, B. IgM and IgE, C. IgM and IgA, D. IgG and IgM', 'role': 'user'}, {'content': 'Answer: C \nExplanation: IgM and IgA contain J chain.', 'role': 'assistant'}]