This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
Aeriolar dilators used in the treatment of CHF 
Select and explain. 
A. Hydralazine, B. Nifedipine, C. Prazosin, D. Enalaprin
A: Hydralazine
Answer: A: Hydralazine 
Explanation: Nifedipine is a calcium channel blocker. Enalapril is an ACE inhibitor. Prazosin is alpha 1 blocker. Hydralazine is an aerial dilator and potassium channel opener (REF.Essentials of medical pharmacology KD TRIPATHI 8 Edition)