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
Most common cause of renal artery stenosis in  young females . 
Select and explain. 
A. Atherosclerosis, B. Fibromuscular dysplasia, C. Takayasu arteritis, D. Poly cystic kidney disease
B: Fibromuscular dysplasia
Answer: B: Fibromuscular dysplasia 
Explanation: Elderly - m/c cause - Atherosclerosis.
Young females - m/c cause - Fibromuscular dysplasia.