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
Best epidemiological tool for investigation of hepatitis B is: 
Select and explain. 
A. Anti-HBsAg, B. Anti-HBcAg, C. Anti-HBeAg, D. HBcAg
B: Anti-HBcAg
Answer: B: Anti-HBcAg 
Explanation: Ans. (b) Anti-HBcAg