This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
Infection /multipilcation of HBsAg is best/commonly diagnosed by - 
Select and explain. 
A. HBeAg, B. HBsAg, C. HBV DNA, D. Anti HBs Ag
A: HBeAg
Answer: A: HBeAg 
Explanation: HBeAg appears in blood concurrently with HBsAg or soon afterwards. Circulating HBeAg is an indicator of active intrahepatic viral multiplication, and the presence in blood of DNA polymerase ,HBV DNA and virions ,reflecting high infectivity. REF:ANANTHANARAYAN AND PANIKER'S TEXTBOOK OF MICROBIOLOGY 9TH EDITION PAGE NO-547