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': "All cause weight gain, except : \nSelect and explain. \nA. Diabetes mellitus, B. Cushing's syndrome, C. Hypothyroidism, D. Insulin secreting tumour", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer is A (Diabetes mellitus) : Endocrine and metabolic causes of weight loss include Hypehyroidism Diabetes mellitus Pheochromocytoma Adrenal insufficiency', 'role': 'assistant'}]