This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Medicine
[{'content': 'The "subclan steal syndrome" occurs due to \nSelect and explain. \nA. Occlusion /stenosis of the veebral aery, B. Occlusion/stenosis of the carotid aery, C. Occlusion of the subclan aery proximal to origin of veebral aery, D. Occlusion of the subclan aery distal to origin of veebral aery', 'role': 'user'}, {'content': 'Answer: C \nExplanation: *Subclan steal:when the arm is used,blood is stolen from the brain the veebral aery .this lead to veebro-basilar ischemia ,which is characterised by dizziness ,coical blindness and/or collapse. Ref Harrison20th edition pg 2456', 'role': 'assistant'}]