In which colour system are red, yellow, and blue considered primary colours?

Correct answer: Traditional pigment system

The governing concept is that the definition of primary colours depends on the medium and colour model. In traditional art education, red, yellow, and blue are treated as the basic pigment colours from which other classroom colours can be mixed, so option B is correct. Light-based screens generally use RGB, while modern printing commonly uses CMYK; neither supports the RYB answer in this question.