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: Anatomy
[{'content': 'Paralysis of opponens muscle leads to loss of thumb.... \nSelect and explain. \nA. Flexion, B. Extension, C. Pinching, D. Abduction', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Flexion', 'role': 'assistant'}]