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
[{'content': 'The drug mainly causing afterload reduction is: \nSelect and explain. \nA. Digoxin, B. Captopril, C. Dobutamine, D. Frusemide', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ACE inhibitors are mixed dilators. They inhibit the generation of angiotensin II resulting in dilatation of aerioles which decreases peripheral vascular resistance and thereby after load. Nitrates are primarily venodilators- decrease Cardiac output mainly calcium channel blockers are mainly aeriolar dilators -decreases peripheral vascular resistance by causing vasodilatation (Ref- ESSENTIAL OF MEDICAL PHARMACOLOGY-K.D TRIPATHI)', 'role': 'assistant'}]