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
Infectivity of HBV is indicated by ? 
Select and explain. 
A. HBeAg, B. HbsAg, C. HBV DNA, D. Anti HBs Ag
A: HBeAg
Answer: A: HBeAg 
Explanation: Ans. is 'a' i.e., H BeAg