Which mixture makes violet?

Correct answer: Red and blue

The relevant colour-wheel rule is that secondary colours are formed by mixing two primary colours. Red and blue combine to produce violet, making option C correct. Red mixed with yellow gives orange, while yellow and blue give green. The pairs containing green are not the standard primary-colour pairs because green is already a secondary colour. In actual paints, the exact violet shade can depend on pigment strength, but violet is the accepted result here.