Which of the following statements about the results of thymectomy for myasthenia gravis are true?

C. The response rate to thymectomy for patients with generalized symptoms is 90%.

DISCUSSION: Overall, improvement can be expected in 90% of patients who undergo thymectomy for generalized myasthenia gravis. In general, the results are more favorable in patients with mild generalized myasthenia. In patients with only ocular symptoms, the benefit following thymectomy is less clear; improvement is documented in 80%. The response rate is even less (30%) in patients with thymoma. Complete remission occurs in 40% to 50% of patients following thymectomy, and the remainder require some continued medical therapy