Do you mean when nucleotides get damaged or when they match to each other incoreectly? (which cuases mutants) Specialized Enzymes repair, different one respond to help different types of damage. Detail the question more, maybe then i can help more.
The answer is C. At first I thought it was D but it actually belongs to clubmosses
The gene p53, also called the guardian of the genome is located on the 17th chromosome in human genomes.
It was given this alternative name because it has a role in response to damage of DNA molecule and in preventing cancer.
The protein product of this gene stops the replication of damaged DNA, activates proteins that repair the DNA damage and if the reparation proteins fail to fix the damage it activates the process of apoptosis or so-called cell death in order to prevent the damaged cell to proliferate and potentially develop into a tumor.
By lowering the activation energy, it helps the reaction go faster.