<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 25-year-old woman comes to the physician because of pain and weakness in her right forearm and hand for several months. Two years ago, she sustained a fracture of her ulnar shaft with dislocation of the radial head that was treated surgically. Physical examination shows mild tenderness a few centimeters distal to the lateral epicondyle. She has marked weakness when attempting to extend her right middle finger. There is radial deviation on extension of the wrist. Sensation is not impaired. Which of the following nerves is most likely affected in this patient?? A: Ulnar nerve, B: Anterior interosseous nerve, C: Superficial radial nerve, D: Posterior interosseous nerve, E: Musculocutaneous nerve,  <response>: This is a clinical vignette describing a patient with right forearm and hand pain and weakness, with a history of previous ulnar shaft fracture and radial head dislocation. The key findings on exam are tenderness distal to the lateral epicondyle, weakness extending the middle finger, and radial deviation on wrist extension. This localizes the lesion to the posterior interosseous nerve, which innervates the extensor muscles in the forearm and hand. Choices A, C and E can be ruled out as they innervate different distributions. Choice B, the anterior interosseous nerve, can also be ruled out as it specifically innervates the flexor pollicis longus, flexor digitorum profundus to index and middle fingers, and pronator quadratus, which do not match the deficits described.D: Posterior interosseous nerve 