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': 'Amyotrophic lateral sclerosis involve- \nSelect and explain. \nA. Anterior horn cell, B. Posterior horn cell, C. Ventral root ganglia, D. Myoneural junction', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]