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 events at the beginning of the final stage of mitosis, we will analyze each option provided in the context of the telophase stage of mitosis.

### Step-by-Step Solution:

1. **Understanding Mitosis Stages**: Mitosis consists of several stages: prophase, metaphase, anaphase, and telophase. The question specifically asks about the final stage, which is telophase.

2. **Identifying Telophase Events**: During telophase, the following key events occur:
- Chromosomes that have been separated during anaphase reach the opposite poles of the cell.
- The nuclear envelope begins to reform around each set of chromosomes.
- Chromosomes start to decondense back into chromatin.
- The nucleolus and other organelles, such as the Golgi apparatus and endoplasmic reticulum, begin to reform.

3. **Analyzing Each Option**:
- **Option A**: "The chromosomes that have reached their respective poles can decondense."
- This is true. In telophase, chromosomes decondense after reaching the poles.
- **Option B**: "Nuclear envelope assembles around the chromosome clusters."
- This occurs during telophase but is not the primary event at the very beginning.
- **Option C**: "Chromosome clusters at opposite spindle poles and their identity is lost as discrete elements."
- This describes metaphase, not telophase.
- **Option D**: "Nucleolus, Golgi complex, and endoplasmic reticulum reform."
- This occurs after telophase, during cytokinesis.

4. **Conclusion**: The correct answer is **Option A**: "The chromosomes that have reached their respective poles can decondense." This accurately describes an event that occurs at the beginning of telophase.

### Final Answer:
**Option A**: The chromosomes that have reached their respective poles can decondense.