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
Bilateral ptosis is not seen in: 
Select and explain. 
A. Marfan's syndrome, B. Myaesthenia gravis, C. Myotonic dystrophy, D. Kearns sayre syndrome
A: Marfan's syndrome
Answer: A: Marfan's syndrome 
Explanation: Ptosis does not occur in Marfans syndrome. Ref: Management of Genetic Syndrome By Suzanne B, 3rd Edition, Page 509 ; Clinical Ophthalmology By Kanski, 3rd Edition, Page 493 and 4th Edition, Page 180-1, 376-77 3. Comprehensive Ophthalmology By A K Khurana, 4th Edition, Page 202