Final answer:
In CMYK, 'K' stands for 'Key,' which is associated with the color black and is used for detail and definition in printing.
Step-by-step explanation:
In the CMYK color process, the 'K' stands for Key. The key plate in traditional printing is usually in black and gives detail and definition to the image. While 'K' is commonly associated with black due to the key plate, it is differentiated to prevent confusion with 'B' which could stand for blue in the RGB color scheme. Inkjet printers produce color images by combining different colored inks. Specifically, the primary colors used in printing are cyan, magenta, and yellow, and when these are mixed together, they subtract light to create different colors. If all these colors are subtracted, it results in black, but in additive color mixing, like with light, adding all primary colors results in white. Therefore, in the context of CMYK, the correct answer to what 'K' stands for is Key, which corresponds to option 1.