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': 'A 5-year-old girl presents with difficulty breathing. On examination, of the oral cavity a 3 cm mass is found in the midline on the posterior aspect of the tongue. The most likely diagnosis is: \nSelect and explain. \nA. Lingual tonsil, B. Lingual thyroid, C. Foreign body stuck to the tongue, D. Dermoid', 'role': 'user'}, {'content': 'Answer: B \nExplanation: An ectopic thyroid gland can be located anywhere from the base of the tongue to the mediastinum. It often results in the failure of descent resulting in either a linginal thyroid or ectopic thyroid in the midline of the neck. The so called lateral aberrant thyroid is usually a metastasis from papillary carcinoma of the thyroid.Angioneurotic edema is an acute allergic reaction, which causes a sudden swelling of the whole tongue with airway obstruction.', 'role': 'assistant'}]