This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
[{'content': 'The pathognomonic feature of rheumatic hea disease is \nSelect and explain. \nA. Aschoff nodule, B. Caterpillar cell, C. McCallum plaques, D. Fibrinous pericarditis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: During acute RF, distinctive lesions occur in the hea, called Aschoff bodies, consisting of foci of T lymphocytes, occasional plasma cells, and plump activated macrophages called Anitschkow cells (pathognomonic for RF). These macrophages have abundant cytoplasm and central round-to-ovoid nuclei (occasionally binucleate) in which the chromatin condenses into a central, slender, wavy ribbon (hence the designation "caterpillar cells").', 'role': 'assistant'}]