This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Predominant class of immunoglobulin during primary immune response is - 
Select and explain. 
A. IgA, B. IgE, C. IgM, D. IgG
C: IgM
Answer: C: IgM 
Explanation: IgM antibodies appear early in the course of an infection and usually reappear, to a lesser extent, after fuher exposure. Ref: Ananthanarayan & Parkers textbook of microbiology 9th edition pg:98