This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Myasthenia Gravis and Muscular dystrophy, Subject name: Medicine
[{'content': 'Which of the following is not seen in Horner syndrome? \nSelect and explain. \nA. Mydriasis, B. Ptosis, C. Anhidrosis, D. Enophthalmos', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Horner syndrome Characterized by damage to sympathetic chain FEATURES ARE- S Sympathetic Injury A Anhidrosis M Miosis P Ptosis L Loss of ciliospinal reflex E Enophthalmos Note: Pan coast tumor (Ca. lung) also can contribute to develop Horner syndrome', 'role': 'assistant'}]