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': 'Hypothyroidism in sub-Himalayan is due to \nSelect and explain. \nA. Iodine, B. Iron, C. Copper, D. Selenium', 'role': 'user'}, {'content': "Answer: A \nExplanation: 'Iodine deficiency in\xa0sub-Himalayan terrain leads to endemic goitre and hypothyroidism”", 'role': 'assistant'}]