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
While performing subjective verification of refraction, the cross cylinder is used to check: 
Select and explain. 
A. Axis of the cylinder to be prescribed, B. Power of the cylinder to be prescribed, C. Both of the above, D. None of the above
C: Both of the above
Answer: C: Both of the above 
Explanation: Ans. Both of the above