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: Pathology
Which of the following Immunoglobulin protects the body surface: 
Select and explain. 
A. IgD, B. IgG, C. IgA, D. IgM
C: IgA
Answer: C: IgA 
Explanation: None