Biology

The correct answer is: C.Anaphase.

During anaphase, the sister chromatids are pulled apart and move toward opposite poles of the cell. This happens after the centromere splits, allowing the chromatids, which were previously joined, to separate and become individual chromosomes.

Here's a quick summary of what happens in the other phases:

A.Prophase: Chromosomes condense, the nuclear envelope begins to break down, and the mitotic spindle begins to form, but sister chromatids are not yet separated....