The correct answer is: Anaphase.
During anaphase, the centromeres of each chromosome split, and the two sister chromatids are pulled apart by the spindle fibers to opposite poles of the cell. This process is mediated by the action of the kinesin motor proteins, which move along the microtubules of the spindle fibers.
Prophase is the first phase of mitosis, and it is characterized by the condensation of the chromosomes and the disappearance of the nuclear envelope.
Metaphase is the second phase of mitosis, and it is characterized by the alignment of the chromosomes at the metaphase plate.
Telophase is the fourth and final phase of mitosis, and it is characterized by the decondensation of the chromosomes and the reformation of the nuclear envelope.
In summary, anaphase is the phase of mitosis during which the centromeres of each chromosome split, and the two sister chromatids are pulled apart by the spindle fibers to opposite poles of the cell.