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 diurnal variation of intraocular pressure is: 
Select and explain. 
A. 0-2 mm of Hg, B. 2-3 mm of Hg, C. 3-6 mm of Hg, D. 6-8 mm of Hg
C: 3-6 mm of Hg
Answer: C: 3-6 mm of Hg 
Explanation: Ans. 3-6 mm of Hg