The shortest period of mitosis is anaphase.
Anaphase is the stage where sister chromatids separate and move to opposite poles of the cell. This process is relatively quick compared to other phases like prophase, metaphase, and telophase. The rapid movement of chromosomes during anaphase ensures that each daughter cell receives a complete and identical set of chromosomes. The reference states that in anaphase, "the sister chromatids break apart, and the chromosomes begin moving to opposite ends of the cell." This action is rapid and deliberate, thus making it the shortest stage of mitosis.
