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': 'Cystic compressible, translucent swelling in the posterior triangle of neck - \nSelect and explain. \nA. Cystic hygroma, B. Branchial cyst, C. Thyroglossal cyst, D. Dermoid cyst', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Cystic hygroma", 'role': 'assistant'}]