This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Anatomy
[{'content': 'Enophthalmus is due to palsy of \nSelect and explain. \nA. Levator palpebrae superioris, B. Superior tarsal muscle, C. Orbital muscle, D. Inferior tarsal muscle', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ref: BD Chaurasia's HUMAN ANATOMY, Volume 3, 4th edition. Enophthalmos (i.e. retraction of the eyeball); is possibly caused by paralysis of the smooth (orbitalis) muscle in the floor of the orbit.", 'role': 'assistant'}]