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
Test for visual acuity in a baby of age <1 year is 
Select and explain. 
A. Electro retinography, B. Electro oculography, C. Snellen's chart, D. Optical Coherence tomography
A: Electro retinography
Answer: A: Electro retinography 
Explanation: Test for visual acuity in an infant is Electro retinography.