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
[{'content': 'The common cause of bilateral internuclear ophthalmoplegia is \nSelect and explain. \nA. Diabetes mellitus, B. Multiple sclerosis, C. Lead toxicity, D. Diphtheria', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Multiple sclerosis It is a demyelinating disorder of unknown etiology, affecting women more often than men, usually in the 15-50 years age group. Pathologically, the condition is characterised by a patchy destruction of the myelin sheaths throughout the central nervous system. Clinical course of the condition: It is marked by remissions and relapses. In this condition, optic neuritis is usually unilateral. Other ocular lesions include bilateral internuclear ophthalmoplegia and vestibular or cerebellar nystagmus. Ref:- A K KHURANA; pg num:- 310', 'role': 'assistant'}]