This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'Which of the following is a prodrug of Penciclovir? \nSelect and explain. \nA. Valacyclovir, B. Valganciclovir, C. Cidofovir, D. Famciclovir', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Famciclovir is the prodrug of penciclovir which is a Guanosine analogue used against herpes.', 'role': 'assistant'}]