This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood Vessels, Subject name: Pathology
[{'content': 'Most common organ affected in polyarteritis nodosa? \nSelect and explain. \nA. Lungs, B. Kidneys, C. Pancreas, D. Spleen', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. b (Kidneys). (Ref. Harrisons Medicine, 18th/ Chapter 326. The Vasculitis Syndromes)PAN is necrotising vasculitis of small and medium sized arteries.Descending order of frequency of involvement of organs in PAN is# Kidney# Heart# Liver# GIT# Muscle# Pancreas# Testis# CNS# Skin', 'role': 'assistant'}]