Question

is the stage of mitosis in which spindle fibers attach to the centromeres of sister chromatids.

Explanation:

In mitosis, the stage where spindle fibers attach to the centromeres of sister chromatids is metaphase. During metaphase, the chromosomes (composed of sister chromatids) align at the cell's equatorial plane, and spindle fibers from the centrosomes attach to the kinetochores at the centromeres of each sister chromatid.

Answer:

Metaphase