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': 'Pemberton’s sign is elicited \nSelect and explain. \nA. Swallowing, B. Raising of arms, C. Extrusion of tongue, D. Extension of neck', 'role': 'user'}, {'content': 'Answer: B \nExplanation: It is used for or large retrosternal goitres.', 'role': 'assistant'}]