This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology Pa 1 (Immune Response, Antigen-Antibody Reactions, Hypersensitivity, Structure of Immune System, Immunodeficiency Disorders), Subject name: Microbiology
Which of the immunoglobulin has Maximum half-life- 
Select and explain. 
A. Ig G, B. Ig A, C. Ig M, D. Ig E
A: Ig G
Answer: A: Ig G 
Explanation: Serum Half-life: IgG (G1, G2, and G4): 23 days (maximum) and Subclass 3 has half-life of 8 days. IgA: 06 days IgM: 05 days IgD: 03 days IgE:2.5 days (minimum)