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: Pharmacology
[{'content': 'Hypothyroidism may be caused by- \nSelect and explain. \nA. Ethionamide, B. Thiocetazone, C. Ethambutol, D. Streptomycin', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Ethionamide", 'role': 'assistant'}]