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
'Safe zone' of the eye ball is: 
Select and explain. 
A. At the limbus, B. 3-4 mm behind the limbus, C. 8-9 mm behind the limbus, D. 12 mm behind the limbus
C: 8-9 mm behind the limbus
Answer: C: 8-9 mm behind the limbus 
Explanation: Ans. 8-9 mm behind the limbus