This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Neck), Subject name: Surgery
[{'content': 'One of the following is an example of painless midline swelling : \nSelect and explain. \nA. Branchial cyst, B. Thyroglossal cyst, C. Cystic hygroma, D. Carotid body tumour', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans is 'b' ie Thyroglossal cyst. Midline swelling of neck from above downwardsLudwig's anginaEnlarged submental lymph nodesSublingual dermoidLipoma in submental regionThyroglossal cyst Subhyoid bursitisGoitre Lipoma & enlarged lymph nodes in the suprasternal space of bumsRetrosternal goiterThymic swelling(A dermoid cyst may occur anywhere in the midline)", 'role': 'assistant'}]