Mitosis is split into 4 phases.
P - prophase
M - metaphase
A - anaphase
T - telophase
During Metaphase, Chromosomes align singly along the metaphase plate.
During Anaphase, kinetochore microtubules shortens and non-kinetochore microtubules lengthens, allowing the chromosomes' centromeres to separate.
Therefore, the answer is anaphase.
P. S. centromeres separates, not split.
