This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cranial Nerve Disorders, Subject name: Medicine
[{'content': 'Unilateral ptosis is NOT seen In? \nSelect and explain. \nA. Myasthenia Gravis, B. Thyroid Opthalmopathy, C. Marfan syndrome, D. Pancoast tumor', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) Thyroid OpthalmopathyRef.: Harrison 19th ed. 12294-95The question is on unilateral ptosis whereas thyroid opthalmopathy has PROPTOSIS.* In myasthenia gravis, due to anti-Ach-receptor blocking antibodies there is ptosis which can be unilateral or asymmetrical which will again appear unilateral.* Marfan syndrome has congenital Ptosis.* Pancoast tumor causes horner syndrome in which unilateral sympathetic chain is compressed leading to Ptosis, Miosis, Anhidrosis, Enopthalmos and loss of Cilio-spinal reflex.', 'role': 'assistant'}]