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: Medicine
[{'content': 'Third nerve palsy with pupillary sparing is seen in all except: \nSelect and explain. \nA. Hypeension, B. Aneurysm of posterior communicating aery, C. Diabetes mellitus, D. Craniopharyngioma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Answer is B (Aneurysm of posterior communicating aery): If the pupil is entirely normal, with all other components of an occulomotor palsy present aneurysm is so rare that an angiogram is seldom indicated. - Harrison Isolated pupil-sparing occulomotor palsy Most cases are thought to result from microvascular infarction of the nerve. Somewhere along its course from the brainstem to the orbit Major risk factors are: Diabetes Hypeension Vascular disease Major presentation is with pain. Spontaneous recovery over a period of months is the rule.', 'role': 'assistant'}]