This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Medicine
True about myasthenia gravis 
Select and explain. 
A. Associated with thymomoa in 3/4 of cases, B. Incremental response seen with repetitive electric stimuli, C. Skeletal muscle function improve after rest, D. Edrophonium test negative
C: Skeletal muscle function improve after rest
Answer: C: Skeletal muscle function improve after rest 
Explanation: *The weakness increase during repeated use and may improve following sleep or rest.only 10% of cases are associated with thymomas 65% with hyperplasia of thymus. Edrophonium test is positive. In electrodiagnostic testing MG patients show a rapid reduction of >10-15% in the amplitude of evoked response. Ref Harrison20th edition pg 2445