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: Surgery
[{'content': 'A middle aged woman presented with history of\nneck swelling which moves with deglutition. Preferred diagnosis is \nSelect and explain. \nA. Cystic hygroma, B. Thyroglossal cyst, C. Thyroid carcinoma, D. Multinodular goitre', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Thyroglossal cyst moves with deglution because it is attached to base of tongue.', 'role': 'assistant'}]