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': 'C.tetani is: \nSelect and explain. \nA. Aerobic, gram-positive, motile bacillus, B. An anaerobic, gram-negative, motile bacillus, C. An anaerobic, gram-positive, nonmotile bacillus, D. An anaerobic, gram-positive, motile bacillus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: An anaerobic, gram-positive, motile bacillus', 'role': 'assistant'}]