Checkpoint proteins at the G1, G2, and M phases of the cell cycle monitor whether crucial cellular process have been completed correctly and the cell cycle can proceed. A mutation in a checkpoint protein can lead to cancer by resulting in the checkpoint protein not functioning properly. Which of the following could be a result of the improper functioning of a checkpoint protein in a cancer cell?

a. Cell division stops.
b. The cell reverts to interphase.
c. There is uncontrolled cell division.
d. The cell dies.