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: Pharmacology
[{'content': 'Longest acting mydriatic among the following is: \nSelect and explain. \nA. Atropine., B. Homatropine., C. Cyclopentolate., D. Tropicamide.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Atropine has a very long duration of action in the eye while shorter action in other organs.', 'role': 'assistant'}]