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
Normal values of Schirmer-I test are: 
Select and explain. 
A. 5 mm, B. 10 mm, C. 15 mm, D. 15 mm or above
D: 15 mm or above
Answer: D: 15 mm or above 
Explanation: Ans. 15 mm or above