Answer:
B. Centrioles
Explanation:
Centrioles are those micro-tubules that are protein filamentous, these micro-tubules are hollow and are part of cytoskeletons in the cells of humans. Spindle fibers are produced from these centrioles. Centrioles first generate asters which generate spindle fibers. These spindle fibers play key role in holding the chromosomes during the cell division on the center equatorial plates or at the poles based on the stage of cell cycle. Spindle fibers help in the movement of chromosomes during the division, they are attached at centromere, centromere is that particular part where two sister chromatids attach.