This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Medicine
Most common cause of renal aery stenosis above 50 years of age is ? 
Select and explain. 
A. Atherosclerosis, B. FMD, C. Takayasu aeritis, D. RCC
A: Atherosclerosis
Answer: A: Atherosclerosis 
Explanation: Atherosclerotic renal aery stenosis is common and prevalence increases with age. Large vessel renal aery occlusive disease can result from extrinsic compression of vessel ,intimal dissection, fibromuscular dysplasia, or most commonly atherosclerotic disease. Ref:Harrison 20 th edition pg no 1906