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: Anatomy
[{'content': 'Ptosis may occur due to damage to: \nSelect and explain. \nA. Trochlear nerve, B. Oculomotor, C. Trigeminal nerve, D. Superior oblique muscle', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ptosis is the drooping eyelid, may be seen in some clinical cases.\nOculomotor ptosis due to paralysis of the levator palpebrae (e.g., transtentorial herniation).\xa0\nOculosympathetic ptosis due to paralysis of the superior tarsal (Muller) muscle as seen in Horner syndrome. This is a very slight ptosis, or pseudoptosis (e.g., Pancoast tumor).', 'role': 'assistant'}]