This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuro Ophthalmology, Subject name: Ophthalmology
[{'content': "Procedure of choice for ptosis in Horner's syndrome? \nSelect and explain. \nA. LPS resection, B. Bilateral sling, C. Unilateral sling, D. Fasanella Servat", 'role': 'user'}, {'content': "Answer: D \nExplanation: Procedure of choice of ptosis in Horner syndrome: Fasanella Servat or Mullerectomy in case of good levator action Superior Tarsal muscle or Muller's muscle is the that is responsible for keeping the upper lid in a raised position after the LPS raises it. It is supplied by the sympathetic system. Hence it is involved in patient's with Horner's Syndrome. As levator remains intact, the degree of ptosis is mild - hence paial ptosis in patients with Horner's Syndrome", 'role': 'assistant'}]