Knudson's two hit hypothesis is characteristically associated with?

Ans is 'c' i.e. Retinoblastoma * Retinoblastoma is a typical example of Knudson's two hit hypothesisKnudson hypothesis (two-hit hypothesis or multiple-hit hypothesis)* It says that cancer is the result of accumulated mutations to a cell's DNA. Knudson's hypothesis refers specifically to the heterozygosity of tumor suppressor genes.* RB gene is a tumor suppressor gene & typical example of this hypothesis.* Knudson noted that inherited retinoblastoma occurs at a younger age than the sporadic disease. In addition, the children with inherited retinoblastoma often developed the tumor in both eyes, suggesting an underlying predisposition & he suggested that multiple "hits" to DNA were necessary to cause cancer.* Retinoblastoma develops when both the normal alleles of the RB genes are inactive or altered. In Hereditary retinoblastoma first genetic change (first hit) in RB gene is inherited from an affected parent, where as second mutation (second hit) occurs in postnatal life and both alleles are lost. In non- hereditary retinoblastoma, both mutations (first and second hits) occur postnataly.