This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Shanti, aged 27 yrs presented with complaints of difficulty in reading near print. There is ptosis and diplopic in all directions. She is having: 
Select and explain. 
A. III CN palsy, B. Myasthenia gravis, C. Presbyopia, D. VI CN palsy
B: Myasthenia gravis
Answer: B: Myasthenia gravis 
Explanation: Myasthenia gravis is characterized by abnormal fatigability of striated muscles after repetitive contraction that improves after rest and often is first manifested by weakness of the extraocular muscles. Unilateral fatiguing ptosis is a frequent first sign, with subsequent bilateral involvement of extraocular muscles, so that diplopia is often an early symptom along with failure of convergence. Unusual ocular presentations may simulate gaze palsies, internuclear ophthalmoplegia, veical nystagmus, and progressive external ophthalmoplegia. Ref: Riordan-Eva P., Hoyt W.F. (2011). Chapter 14. Neuro-Ophthalmology. In P. Riordan-Eva, E.T. Cunningham, Jr. (Eds), Vaughan & Asbury's General Ophthalmology, 18e.