This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Considerations - Definition, Classification, Pathogenesis, Subject name: Ophthalmology
Normal intraocular pressure is - 
Select and explain. 
A. 7 - 14 mm Hg, B. 2.1 - 6 mm Hg, C. 10 - 21mm Hg, D. 16 - 32 mm Hg
C: 10 - 21mm Hg
Answer: C: 10 - 21mm Hg 
Explanation: Ans. is 'c' i.e., 10-21 mm Hg o The intraocular pressure (IOP) refers to the pressure exerted by intraocular fluids on the coats of the eyeball. The normal IOP varies between 10 and 21 mmHg.