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': 'A 45-year-old woman is admitted to the hospital with neck pain. An MRI examination reveals a herniated disk in the cervical region. Physical examination reveals weakness in wrist extension and paranesthesia on the back of her arm and forearm. Which of the following spinal nerves is most likely injured? \nSelect and explain. \nA. C5, B. C6, C. C7, D. C8', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The seventh cervical nerve makes a major contribution to the radial nerve, and this nerve is the prime mover in wrist extension. The dermatome of C7 is in the region described.', 'role': 'assistant'}]