Final answer:
The correct answer is a proto-oncogene, which when mutated can cause uncontrolled cell division by overriding cell cycle checkpoints and may lead to cancer. The correct answer is option b).
Step-by-step explanation:
A mutated gene that codes for an altered version of Cdk (cyclin-dependent kinase) that remains active without the presence of cyclin can lead to uncontrolled cell division as it may send the cell cycle past checkpoints without all required conditions being met.
This type of gene is known as a proto-oncogene. When the proto-oncogene is altered it becomes an oncogene, which can then contribute to cancer by increasing the rate of cell cycle progression. In contrast, a tumor suppressor gene is a segment of DNA.
It codes for proteins that can prevent the cell from undergoing uncontrolled division, much like brakes prevent a car from crashing. Therefore, the correct answer to the question is a proto-oncogene, which in its mutated form can override cell cycle checkpoints and potentially lead to cancer.