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: Medicine
[{'content': 'Which of the following drugs is used for Irritable Bowel Syndrome of the constipating type - \nSelect and explain. \nA. Lubipro stone, B. Cholestyramine, C. Alosetron, D. Rifaximin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]