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: Microbiology
[{'content': 'Most common cause of "Polymyositis" is \nSelect and explain. \nA. Pseudomonas, B. Brucella, C. Streptococcus, D. Staphylococcus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Staphylococcus', 'role': 'assistant'}]