This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ocular motility and squint, Subject name: Ophthalmology
III nerve palsy with pupillary sparing is seen in - 
Select and explain. 
A. Craniopharyngioma, B. Hypotension, C. Aneurysm of post, communicating aery, D. DM
D: DM
Answer: D: DM 
Explanation: Pupil-sparing oculomotor nerve palsy is often assumed to be caused by ischemic injury such as hypeension and diabetes mellitus. Sometimes compressive lesion can cause pupil-sparing oculomotor nerve palsy with a sho interval from the onset of symptoms to diagnosis.