Final answer:
The correct stage of mitosis where chromosomes align at the metaphase plate and are attached to microtubules at their kinetochores is Metaphase.
Step-by-step explanation:
The stage of mitosis where chromosomes are aligned at the metaphase plate, attached to microtubules at their kinetochores, is Metaphase. During metaphase, the sister chromatids are maximally condensed and attached to spindle fibers from opposite poles of the cell. These spindle fibers or microtubules attach at a region on the chromosome known as the kinetochore. The sister chromatids align along a plane termed the metaphase plate, which is located equidistant from the two spindle poles. Therefore, the correct answer to the question is C) Metaphase.