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
Most probable diagnosis in child with midline swelling is ? 
Select and explain. 
A. Thyroglossal cyst, B. Thyroid gland, C. Cystic hygroma, D. Dermoid cyst
A: Thyroglossal cyst
Answer: A: Thyroglossal cyst 
Explanation: None