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
In chronic Hepatitis B infection, which one of the following markers is indicative of active viral replication and the corresponding risk of disease transmission ? 
Select and explain. 
A. HBe antigen, B. HBs antigen, C. Anti - HBe, D. Anti - HBs
A: HBe antigen
Answer: A: HBe antigen 
Explanation: Ans. is 'a' i.e., HBe antigen