This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tumors, Subject name: Ophthalmology
Retinoblastoma can occur bilaterally in how many percentage of the cases? 
Select and explain. 
A. 10-15%, B. 15-20%, C. 20-25%, D. 25-30%
D: 25-30%
Answer: D: 25-30% 
Explanation: 25-30% bilateral involvement . Seen in childrens between 1-2 yrs of age. Ref : ak khurana 6th edition