This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitreous and retina, Subject name: Ophthalmology
[{'content': 'Normal intraocular pressure is \nSelect and explain. \nA. 2.1-6 mm Hg, B. 7-14 mm Hg, C. 10-21 mm Hg, D. 16-32 mm Hg', 'role': 'user'}, {'content': 'Answer: C \nExplanation: (Refer: AK Khurana Comprehensive Ophthalmology, 6th edition, pg no. 223)The intraocular pressure (IOP) refers to the pressure exeed by intraocular fluids on the coats of the eyeball. The normal IOP varies between 10 and 21 mmHg.', 'role': 'assistant'}]