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': 'Concomitant administration of this drug with organic nitrates is contraindicated due to marked potentiation of vasodilatory action leading to profound hypotension. This drug is: \nSelect and explain. \nA. Propranolol, B. Fluoxetine, C. Hydrochlorothiazide, D. Sildenafil', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]