This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hepatitis, Subject name: Medicine
All the following are used for treatment of chronic Hepatitis B except? 
Select and explain. 
A. Entecavir, B. Telbivudine, C. Zidovudine, D. Lamivudine
C: Zidovudine
Answer: C: Zidovudine 
Explanation: Entecavir Entecavir, an oral cyclopentyl guanosine analogue polymerase inhibitor, appears to be the most potent of the HBV antivirals. Telbivudine Telbivudine, a cytosine analogue, appears to be similar in efficacy to entecavir; however, it is slightly less potent in suppressing HBV DNA. Lamivudine Lamivudine inhibits reverse transcriptase activity of both HIV and HBV and is a potent and effective agent for patients with chronic hepatitis B.