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': 'Viagra like medicine is given in which condition: March 2007 \nSelect and explain. \nA. Pulmonary hypeension, B. Essential hypeension, C. Malignant hypeension, D. Hypeension in pregnancy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A: Pulmonary Hypeension Since NO is an impoant regulator of pulmonary vascular resistance, PDE-5 inhibitors lower pulmonary aerial pressure. Sildenafil is more selective for pulmonary circulation than vardenafil, and is the only PHosphoDiEsteras-5 inhibitor shown to improve aerial oxygenation in pulmonary hypeension. Sildenafil has now become the drug of choice for pulmonary aerial hypeension.', 'role': 'assistant'}]