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': 'Neurotoxin of tetanus acts on \nSelect and explain. \nA. Synapse, B. Muscle, C. Brain, D. Spinal Cord', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]