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
Which of the following is the drug used for testing errors of refraction in a 7-year-old girl? 
Select and explain. 
A. Atropine ointment, B. Tropicamide, C. Phenylephrine, D. Homatropine
A: Atropine ointment
Answer: A: Atropine ointment 
Explanation: Atropine is a powerful cycloplegic. It is needed to overcome the muscle tone.