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: Medicine
Early diagnosis of active hepatitis B Infection is done by: 
Select and explain. 
A. IgM HBcAg antibody, B. HBsAg, C. HBcAg, D. IgE HBsAg antibody
A: IgM HBcAg antibody
Answer: A: IgM HBcAg antibody 
Explanation: None