This is a subtle distinction that is necessary to understand. For one thing, the centromere is DEFINED as the as a sequence within the DNA chromatin that is responsible for attaching the sister chromatids to one another. In most publications, the sequence at the centromere is extremely repetitive and usually located within heterochromatin (chromatin that is extremely inaccessible for  . The centromere serves as the foundation for assembly for the kinetochore, which is a protein complex that is essential for attaching to the microtubules. Currently, the kinetochore is thought to be a accumulated complex of 80+ proteins, and the main function of it is to actually to serve as a docking point for microtubules.

The answer cannot be A because centromeres have nothing to do with transcription, and furthermore, I mentioned above that the centromere tends to be found in heterochromatin (which are regions that are extremely not under transcriptional regulation). The answer is not C because that is the function of the kinetochores – not centromeres. The answer is also not D because the centromeres are not intended to serve as separating points – they’re made to hold the sister chromatids together. To further facilitate this understanding, please check the image below: