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': "p-ANCA is characteristic for: \nSelect and explain. \nA. PAN, B. Microscopic polyangitis, C. Wegener's granulomatosis, D. Henoch-Schonlein purpura", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Answer is B (Microscopic polyangitis) : PAN can broadly be classified into Classic PAN (now referred to an PAN) Classified as Medium Vessel Vasculitis Necrotizing inflammation of small & medium sized aeries. No involvement of capillaries & venules Pulmonary vasculature is not involved. ANCA mostly negative (Rarely p-ANCA may be seen) Microscopic PAN (now called microscopic polyangitis) Classified as small vessel vasculitis Necrotizing inflammation of small & medium sized aeries. Capillaries & venules are involved Pulmonary vasculature is involved. ANCA positive (p-ANCA)', 'role': 'assistant'}]