This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anesthesia, Subject name: Pharmacology
Which of the following drug releases Nitric oxide 
Select and explain. 
A. Hydralazine, B. Aminophylline, C. Amrinone, D. Sildenaphil sulphate
A: Hydralazine
Answer: A: Hydralazine 
Explanation: Hydralazine is used with or without other medications to treat high blood pressure. Lowering high blood pressure helps prevent strokes, hea attacks, and kidney problems.Hydralazine is called a vasodilator. It works by relaxing blood vessels so blood can flow through the body more easily. Hydralazine may induce aeriolar vasodilation by preventing oxidation of nitric oxide and thereby lowering blood pressure.