For the majority of people, Social Security Disability benefits are not taxable. This is true for people who have income in addition to disability benefits as well as those who do not. (Most of the one-third of disability recipients who do pay taxes on benefits receive SSDI benefits, not SSI.
Mixing all three gives black. The CMYK color model (process color, four color) is a subtractive color model, used in color printing, and is also used to describe the printing process itself. CMYK refers to the four inks used in some color printing: cyan, magenta, yellow, and key (black).
Also see hue, saturation, and brightness. CMYK is a scheme for combining primary pigments. The C stands for cyan (aqua), M stands for magenta (pink), Y for yellow, and K for Key. The key color in today's printing world is black but it has not always been.