This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'Most common cause of renal artery stenosis in  young females . \nSelect and explain. \nA. Atherosclerosis, B. Fibromuscular dysplasia, C. Takayasu arteritis, D. Poly cystic kidney disease', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Elderly - m/c\xa0cause - Atherosclerosis.\nYoung females - m/c cause -\xa0Fibromuscular dysplasia.', 'role': 'assistant'}]