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': 'Pathology in motor neuron disease is at? \nSelect and explain. \nA. Anterior horn cells, B. Posterior column tracts, C. Spinothalamic tract, D. Peripheral nervous system', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]