Final answer:
The G0 phase is a stage in which cells are not actively dividing; they are quiescent, either temporarily or permanently, until specific conditions prompt them to re-enter the cycle or they continue to perform specialized functions without division.
Step-by-step explanation:
The correct answer is c. State in which cells are not multiplying at all. The G0 phase, sometimes referred to as 'G zero', is a quiescent stage in the cell cycle. During the G0 phase, cells are not actively preparing to divide. Instead, they have exited the cell cycle and remain in a state of dormancy. This can be a temporary state until conditions are right for the cell to re-enter the cycle or a permanent state for cells that no longer divide, such as mature cardiac muscle and nerve cells.
Importantly, cells in the G0 phase can be called back into the cell cycle by external signals or continue to perform their specialized functions without dividing. Some cells enter Go temporarily until an external signal triggers the onset of G₁, while other cells that never or rarely divide remain in Go permanently