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': 'Anterior m i d line swelling of neck is: March 2013 (g) \nSelect and explain. \nA. Branchial cyst, B. Thyroglossal cyst, C. Cystic hygroma, D. Carotid body tumour', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B i.e. Thyroglossal cyst', 'role': 'assistant'}]