Attachment of spindle fibres to kinetochores of chromosomes becomes evident in:

Options

A. Anaphase
B. Telophase
C. Prophase
D. Metaphase

Answer

To solve the question regarding when the attachment of spindle fibers to kinetochores of chromosomes becomes evident, we can break down the process of cell division, particularly focusing on the phases of mitosis:

### Step-by-Step Solution:

1. **Understanding Mitosis Phases**: Mitosis consists of several phases: Prophase, Metaphase, Anaphase, and Telophase. Each phase has distinct events that occur.

2. **Prophase**: During prophase, the chromatin condenses into visible chromosomes, and the nucleolus disappears. However, the spindle fibers have not yet attached to the kinetochores at this stage.

3. **Prometaphase**: This phase is often included in discussions of prophase. Here, the nuclear envelope breaks down, and kinetochores form at the centromeres of the chromosomes. Spindle fibers begin to attach to these kinetochores.

4. **Metaphase**: In metaphase, the chromosomes align at the metaphase plate (the equatorial plane of the cell). At this point, each sister chromatid is attached to spindle fibers via their kinetochores. This is the key phase where the attachment of spindle fibers to kinetochores becomes evident.

5. **Anaphase**: During anaphase, the sister chromatids are pulled apart towards opposite poles of the cell. The attachment of spindle fibers to kinetochores is still present, but the focus is on the separation of chromatids.

6. **Telophase**: In telophase, the separated chromatids reach the poles, the nuclear envelope begins to reform, and the spindle fibers disassemble. The attachment of spindle fibers to kinetochores is no longer evident as the chromosomes are now at opposite ends.

### Conclusion:
The attachment of spindle fibers to kinetochores of chromosomes becomes evident in **Metaphase**.

**Final Answer**: D. Metaphase