This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hepatic encephalopathy & hepatic failure, Subject name: Medicine
Most common cause of Fulminant hepatic failure? 
Select and explain. 
A. HAV, B. HBV, C. HCV, D. HDV
D: HDV
Answer: D: HDV 
Explanation: Hepatitis D virus Hepatitis D accounts for maximum number of fulminant cases of viral hepatitis, a sizable propoion of which are associated with HBV infection. Superinfection with HDV in patients of chronic hepatitis B infection leads to fulminant hepatic failure