What specifically do most people inherit when they inherit a predisposition to a particular cancer such as retinoblastoma?

A) a mutation that causes the overexpression of a DNA repair gene
B) a mutation that causes telomerase to have reduced expression in somatic cells
C) a deleterious mutation in one copy of a tumor-suppressor gene
D) a deletion that removes one copy of an oncogene
E) an extra X chromosome from the mother