This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Ophthalmology
Visual acuity in infants is tested with the help of 
Select and explain. 
A. Landolt's rings, B. '4' dot test, C. Perimeter, D. Slit lamp
A: Landolt's rings
Answer: A: Landolt's rings 
Explanation: .