This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuro-ophthalmology, Subject name: Ophthalmology
[{'content': 'Unilateral sudden complete loss of vision (Amaurosis fugax) is due to lesion in - \nSelect and explain. \nA. Internal carotid aery, B. Middle cerebral aery, C. Anterior cerebral aery, D. Basilar aery', 'role': 'user'}, {'content': "Answer: A \nExplanation: Amaurosis fugax refers to sudden temporary and painless monocular visual loss occurring due to a transient failure of retinal circulation. COMMON CAUSES: Carotid transient ischemic attack, embolization of retinal circulation, papilloedema, giant cell aeritis, Raynaud's disease, migraine, as a prodromal symptom of central retinal aery or carotid aery occlusion, hypeensive retinopathy, and venous stasis retinopathy. Reference: Comprehensive Opthalmology, A K Khurana; 6th edition.pg no331.", 'role': 'assistant'}]