At the beginning of the final stage of mitosis,

Options

A. The chromosomes that have reached their respective poles decondense .
B. Nuclear envelope assembles around the chromosome clusters .
C. Chromosomes cluster at opposite spindle poles and their identity is lost as discrete elements .
D. Nucleolus , golgi complex and ER reform .

Answer

To solve the question regarding the final stage of mitosis, let's break it down step by step:

### Step-by-Step Solution:

1. **Understanding Mitosis Stages**:
- Mitosis consists of several stages: prophase, metaphase, anaphase, and telophase. Each stage has distinct characteristics and events.

2. **Identifying the Final Stage**:
- The final stage of mitosis is **telophase**. This is the stage where the chromosomes have been separated and are at opposite poles of the cell.

3. **Analyzing the Options**:
- We need to evaluate the provided options based on what occurs during telophase.

4. **Option 1**: "Chromosomes that have reached their respective poles decondense."
- In telophase, chromosomes indeed reach the poles and begin to decondense, returning to a less coiled state. This option is correct.

5. **Option 2**: "Nuclear envelope assembles around the chromosome cluster."
- The nuclear envelope starts to reform during telophase, but it is not fully assembled at the very beginning of this stage. This option is partially correct but not fully representative of the very beginning of telophase.

6. **Option 3**: "Chromosome cluster at opposite spindle poles and their identity is lost at discrete element."
- This describes anaphase, where sister chromatids are pulled apart to opposite poles. Therefore, this option is incorrect for telophase.

7. **Option 4**: "Nucleosome, Golgi complex, and ER reform."
- While organelles begin to reform during telophase, the complete reformation occurs during cytokinesis, which follows telophase. Thus, this option is also incorrect.

8. **Conclusion**:
- The most accurate option that describes the beginning of telophase is **Option 1**: "Chromosomes that have reached their respective poles decondense."

### Final Answer:
The correct answer is **Option 1**: "Chromosomes that have reached their respective poles decondense."