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
Longest acting mydriatic among the following is: 
Select and explain. 
A. Atropine., B. Homatropine., C. Cyclopentolate., D. Tropicamide.
A: Atropine.
Answer: A: Atropine. 
Explanation: Atropine has a very long duration of action in the eye while shorter action in other organs.