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': 'The characteristic "sulfur grains"of actinomycosis are composed chiefly of \nSelect and explain. \nA. Organisms, B. Neutrophils and monocytes, C. Monocytes and lymphocytes, D. Eosinophils', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]