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': 'Which of the following drugs cause constipation \nSelect and explain. \nA. Propanolol, B. Verapamil, C. Nitroglycerin, D. Captopril', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Refer kDT 6/e p 530 All Calcium channel blockers can cause smooth muscle relaxation in blood vessels and extravascular organs( bronchus GIT urinary bladder and uterus)', 'role': 'assistant'}]