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: Pathology
[{'content': 'Necrotising arterioritis with fibrinoid necrosis is characteristic of \nSelect and explain. \nA. Immediate hypersensitivity, B. Ag-Ab complex mediated, C. Cell mediated immunity, D. Cytotoxic mediated', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Fibrinoid necrosis is a special form of necrosis, visible by light microscopy , usually in immune reaction in which complexes of antigens and antibodies are deposited in the walls of arteries. The deposited immune complexes together with fibrin that has leaked out of vessels produce a bright pink and amorphous appearance on H & E preparation called fibrinoid.', 'role': 'assistant'}]