D. just before or just after the separation of sister chromatids
Explanation:
The mitotic spindle is a structure of the eukaryotic cell cytoskeleton involved in mitosis. Their function is to separate the sister chromatids during cell division so that they are included in the daughter cells. It consists of longitudinally aligned microtubule bundles that together have an ellipsoid-like shape.
For this reason, we can state that if a drug that prevents disassembly of the mitotic spindle paralyzes the cell cycle immediately before or shortly after separation of the sister chromatids.
