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
A 25-year-old woman presents with symptoms of fatigue and weakness. On examination, there is diplopia, ptosis, weakness, and fatigability of muscles on repeated use. Which of the following is the most likely diagnosis? 
Select and explain. 
A. myasthenia gravis, B. multiple sclerosis, C. TIAs, D. muscular dystrophy
A: myasthenia gravis
Answer: A: myasthenia gravis 
Explanation: The distribution of muscle weakness is characteristic with early involvement of the cranial nerves, especially the lids and extraocular muscles. Women are more frequently affected than men (3:2 ratio), and the age for peak incidence in women is in the third or fourth decade.