This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Malabsorbtion Syndrome, Subject name: Medicine
[{'content': 'All cause diarrhea except; \nSelect and explain. \nA. Diabetes, B. Hypercalcemia, C. Hypehyroidism, D. Irritable bowel syndrome', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Hypercalcemia increases the tone of sphincters of the gut leading to refractory constipation. Autonomic dysfunction in diabetes explains the diarrhea. Due to sympathetic activity increase in thyrotoxicosis there is a reduction in small bowel transit time explaining the diarrhea. IBS has variable presentation between diarrhea and constipation', 'role': 'assistant'}]