This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Orbit, Subject name: Anatomy
[{'content': 'Muller muscle is supplied by which nerve: \nSelect and explain. \nA. Facial nerve, B. Sympathetic nerve, C. Trigeminal nerve, D. Vagus nerve', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. (b) Sympathetic nerveRef.-.BDC 6th ed. Vol-III/74* Ptosis is drooping of eyelid.* Eyelid is comprised of 4 muscles:Muscles, their innervation and functionMuscleCN innervationFunction* LPSIIIOpens the eyelid* Muller's muscleT1 (NOT a CN; sympathetic nerve)Opens eyelid when LPS tired* FrontalisVIICloses the eyelid* Orbicularis oculiVIICloses the eyelid* CN III palsy leads to drooping of eyelid (Ptosis).* CN VII palsy may also cause ptosis.Also Know*All the extraocular muscles are supplied by CN III except lateral rectus and superior oblique.* Lateral rectus supplied by- CN VI* Superior oblique supplied by- CN IVRemember- LR6; So4", 'role': 'assistant'}]