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
[{'content': 'Which of the following is/ are contrast sensitivity testing chas? \nSelect and explain. \nA. Pellirobsons, B. Snellen type cha, C. Regan cha, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. is d i.e., All of the above Contrast Sensitivity Testing is done with the help of following chas: Pelli-Robson cha The Regan cha StandardSnellen-type', 'role': 'assistant'}]