Decision of `G_(0)`-phase occurs

Options

A. Towards the end of `G_(1)`-phase
B. Before middle of `G_(1)`-phase
C. At the end of telophase
D. Towards end of cytokinesis

Answer

### Step-by-Step Solution:

1. **Understanding the Cell Cycle**: The cell cycle consists of various phases including G1, S, G2, and M phases. Each phase has specific functions and prepares the cell for division.

2. **Identifying the G0 Phase**: The G0 phase is often referred to as a resting phase. It is a state where the cell is not actively preparing to divide and can be considered a quiescent state.

3. **Location of G0 Phase**: The G0 phase can occur at different points in the cell cycle, primarily before or during the G1 phase. It is a point where the cell has decided not to proceed with division.

4. **G1 Phase Overview**: The G1 phase is the first gap phase following cell division, where the cell grows and prepares for DNA synthesis. It is crucial for the cell to assess its environment and internal conditions before committing to division.

5. **Determining the Timing of G0 Phase**: The decision to enter the G0 phase typically occurs before or in the middle of the G1 phase. This is when the cell evaluates whether conditions are favorable for division.

6. **Excluding Incorrect Options**: The end of the G1 phase, end of telophase, and during cytokinesis are not correct locations for the G0 phase. The G0 phase is not a part of the active cell division process but rather a resting state.

7. **Conclusion**: Therefore, the correct answer is that the decision to enter the G0 phase occurs before or in the middle of the G1 phase.