This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Medicine
[{'content': 'Most common chronic viral illness is caused by: \nSelect and explain. \nA. Hepatitis A, B. Hepatitis B, C. Hepatitis C, D. Hepatitis D', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. (c) Hepatitis CRef.: Harrison 18th edition, chapter 306* Chronic hepatitis follows acute hepatitis C in 50-70% of cases; chronic infection is common even in those with a return to normal in aminotransferase levels after acute hepatitis C, adding up to an 85% likelihood of chronic HCV infection after acute hepatitis C.* Infection at birth with hepatitis B is associated with clinically silent acute infection but a 90% chance of chronic infection, while infection in young adulthood in immunocompetent persons is typically associated with clinically apparent acute hepatitis but a risk of chronicity of only approximately 1%.', 'role': 'assistant'}]