The correct answer is C - lateral elbow tendinopathy. Given the patient's age and the physical findings, osteoarthritis of the radiocapitellar joint is unlikely. The symptoms of radial tunnel syndrome are very similar to those of lateral elbow tendinopathy (LET), so it would be impossible to rule one or the other out at this stage in the examination. For example, as in LET, pain from radial tunnel syndrome often starts near the lateral epicondyle. One difference between radial tunnel syndrome and LET is the exact location of the pain. In LET, the pain starts where the tendon attaches to the lateral epicondyle, whereas in radial tunnel syndrome, the pain is centered about two inches further down the arm, over the spot where the radial nerve goes under the supinator muscle.