Which one of the following is not a diagnostic criterion for rheumatoid arthritis according to the American Rheumatism Association?

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 and/or periarticular osteopenia in hand and/or wrist joints