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: Radiology
[{'content': "The 'String of beads' or sausage appearance of the renal aery is due to \nSelect and explain. \nA. Fibromuscular dysplasia, B. Subadventitial fibroplasia, C. Medial fibroplasia with aneurysms, D. Outercoat fibroplasia with aneurysms", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Fibromuscular dysplasia', 'role': 'assistant'}]