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
[{'content': 'Retinoblastoma can occur bilaterally in how many percentage of the cases? \nSelect and explain. \nA. 10-15%, B. 15-20%, C. 20-25%, D. 25-30%', 'role': 'user'}, {'content': 'Answer: D \nExplanation: 25-30% bilateral involvement . Seen in childrens between 1-2 yrs of age. Ref : ak khurana 6th edition', 'role': 'assistant'}]