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: Social & Preventive Medicine
Epidemiologic study of Hepatitis B is - 
Select and explain. 
A. HBe Ag, B. HBc Ag, C. HBs Ag is used, D. Anti HBc
D: Anti HBc
Answer: D: Anti HBc 
Explanation: None