Answer: A
B18.0 is the correct code for this case because it codes for chronic viral hepatitis B with delta agent. Since the patient had a yellow color of the skin, nausea, etc. for the last 5 months, it denotes the chronic nature of hepatitis.
Option B is not correct because B18.1 is used to code for chronic viral hepatitis B without a delta agent.
Option C is not correct because B18.2 is used to code for chronic viral hepatitis C.
Option D is not correct because B19.1 is used to code for unspecified viral hepatitis B.