During which phase or phase of cell division, the morphology of the chromosomes is best studied?

The correct answer is: Metaphase.

In metaphase, the chromosomes are aligned at the center of the cell, making them easy to see and study. The chromosomes are also condensed in metaphase, which makes them easier to distinguish from each other.

In prophase, the chromosomes are still decondensed and difficult to see. In anaphase, the chromosomes are moving to opposite poles of the cell, making them difficult to study. In telophase, the chromosomes are decondensing and forming new nuclei, making them difficult to study.

Therefore, the best time to study the morphology of the chromosomes is during metaphase.