Which of the Following Statements Explains the Molecular Clock Theory

Which of the following statements explains the molecular clock theory?

A) Telomeres that cap the ends of chromosomes become shorter with each cell division, and their loss eventually stops the chromosomes from replicating.
B) Mistakes in the replication of cells or buildup of damaging byproducts from biological processes eventually destroys the organism.
C) The unstable oxygen formed normally during metabolism can damage cells by initiating reactions that break down cell membranes.
D) Fast-paced living shortens one's life span.
E) The genetic code directs cells to divide a certain number of times during their life span.