This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Thyroid Gland), Subject name: Surgery
[{'content': 'Secretory sinus in neck, moving upon deglutination: \nSelect and explain. \nA. Branchial sinus, B. Pilonidal cyst, C. Thyroglossal fistula, D. Sublingual dermoid cyst', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. (c) Thyroglossal fistulaRef: Dhingra's ENT 5th ed. / 398* Sublingual dermoid cyst present as midline submental swelling. This cyst is not attached to foramen cecum and hence doesn't move upon tongue protrusion or upon deglutition.* The thyroglossal cyst classically moves upwards with swallowing and notably with tongue protrusion, as it is attached to foramen cecum. It merely indicates attachment to the hyoid bone.", 'role': 'assistant'}]