This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper Extremity, Subject name: Anatomy
[{'content': 'Pen Test is for: \nSelect and explain. \nA. Median Nerve, B. Ulnar Nerve, C. Radial Nerve, D. Posterior Interosseus Nerve', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. Median NervePen test (to check the paralysis of abductor pollicis brevis) - The patient is unable to touch the object held above the thumb at right angle to palm. This test is used to check the integrity of median nerve.', 'role': 'assistant'}]