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
Which HBV gene codes for HBe Ag? 
Select and explain. 
A. PreC+C, B. S, C. X, D. C
A: PreC+C
Answer: A: PreC+C 
Explanation: Ans. a (Pre C+C) (Ref. Ananthanarayan Microbiology 7th/pg. 552)HBV# It is a partially double-stranded deoxyribonucleic acid (DNA) virus packaged with a core protein (HBcAg) and DNA polymerase, and enclosed by envelope proteins (HBsAg).# Following receptor-mediated entry into hepatocytes, the virus enters the nucleus, where its DNA is frequently integrated into the host genome.Protein synthesis proceeds from four open reading frames:# The envelope proteins - Major, Middle, and Large (HBsAg) from the -S gene, pre-Sl, and pre-S2 gene sequences;# The e antigen (HBeAg) and core protein (HBcAg) from the -C gene and pre-C gene sequence;# The DNA polymerase protein from the -P gene; and# The transactivator X-protein from the -X gene.