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
The most common type of refractive error is: 
Select and explain. 
A. Hypermetropia, B. Myopia, C. Astigmatism, D. None of the above
C: Astigmatism
Answer: C: Astigmatism 
Explanation: Ans. Astigmatism