30 year old woman with proximal muscle weakness?

A 30 year old woman presented to the OPD with proximal muscle weakness, ptosis and easy fatigability. Which of following is the most sensitive test to arrive at a diagnosis?
A. Single fiber electromyography
B. Muscle biopsy
C. Measurement of creatinine phosphokinase levels
D. Edrophonium test

Correct answer : A. Single fiber electromyography

Myasthenia gravis – Reversal of ptosis after edrophonium test

The history and clinical features are suggestive of myasthenia gravis.
Single fiber electromyography is the most sensitive test for the diagnosis of myasthenia gravis
Detection of acetylcholine receptor antibodies is the most specific test
If single fiber electromyography is not given among the options, the next best choice is edrophonium test