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': 'Diffuse toxic goitre is characterized by -a) Primary thyroid diseaseb) Secondary thyroid diseasec) It is due to autoimmune thyroid stimulating hormone (TSH) antibodyd) It is due to TSH receptor antibody \nSelect and explain. \nA. b, B. ad, C. ac, D. ab', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]