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
'Knudson\'s two stage hypothesis is for – 
Select and explain. 
A. Glaucoma, B. Retinoblastoma, C. Optic glioma, D. Meningioma
B: Retinoblastoma
Answer: B: Retinoblastoma 
Explanation: Deletion or inactivation of RB gene by two mutations (Knudson's two hit hypothesis) results in occurrence of retinoblastoma.