<prompt> Which one of the following is not a diagnostic criterion for rheumatoid arthritis according to the American Rheumatism Association?Raised rheumatoid factor.Symmetric swelling arthritis for at least 6 weeks.Symmetrical muscle weakness.Rheumatoid nodules.  <response>: Ans. C. Symmetrical muscle weakness.Rheumatoid arthritis is defined by the presence of four or more of the following criteria according to the American Rheumatism Association:a. Morning stiffness in and around joints lasting at least 1 hour before maximal improvement, present for at least 6 weeksb. Soft tissue swelling arthritis of three or more joint areas observed by a physician, present for at least 6 weeksc. Swelling arthritis of the proximal interphalangeal, metacarpophalangeal or wrist joints for at least 6 weeksd. Symmetric swelling arthritis for at least 6 weekse. Rheumatoid nodulesf. The presence of rheumatoid factorg. Radiographic erosions andor periarticular osteopenia in hand andor wrist joints 