Final answer:
The nuclei stained with a quick dip and viewed under a microscope appear blue, as they are commonly stained with DAPI, which emits blue fluorescence.
Step-by-step explanation:
The color of the nuclei, when stained with a quick dip and viewed under a microscope, would appear blue. This is because, as per the various examples cited, nuclei are commonly stained with 4',6-diamidino-2-phenylindole (DAPI), a dye that adsorbs ultraviolet light and emits blue fluorescence. Therefore, the correct answer to which color the quick dip made the nuclei is (a) Blue.