We Would All Have Many More Mutations in Our Genes

We would all have many more mutations in our genes if not for the _____.

A) activity of repair enzymes
B) death of all mutant cells,removing them from our bodies
C) fact that everybody carries a "good" allele to counter every "bad" allele
D) fact that dividing cells remove all their mutations when they replicate their DNA
E) fact that mutations tend to cancel each other out,leaving mostly functional genes