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: Pathology
'Knudson's two-hit' hypothesis is associated with 
Select and explain. 
A. Crohn's disease, B. Melanoma, C. Ulcerative colitis, D. Retinoblastoma
D: Retinoblastoma
Answer: D: Retinoblastoma 
Explanation: Harshmohan textbook of pathology 7th edition. 
☆ Familial retinoblastoma comprises 40% of cases and may be bilateral. 
In this cases, all somatic cells inherit one mutant RB gene from a carrier parent. Later during life, the other mutational event of 2nd allele affecting the somatic cells occurs.
This forms the basis of two hot hypothesis given by Knudson in 1971.