This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neck, Subject name: Surgery
[{'content': 'Tumor appears at the earliest after birth. \nSelect and explain. \nA. Cystic hygroma, B. Branchial cyst, C. Lymphoma, D. Sternomastoid tumor', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Cystic hygromaRef: Bailey and Love 26th edition, Page700* Earliest swelling one can note in human beings in Cystic Hygroma.* It can present as obstructed labor', 'role': 'assistant'}]