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
If a patient were genetically unable to make J chains, which immunoglobulins would be affected? 
Select and explain. 
A. IgG and IgA, B. IgM and IgE, C. IgM and IgA, D. IgG and IgM
C: IgM and IgA
Answer: C: IgM and IgA 
Explanation: IgM and IgA contain J chain.