If a painter wants to create a dark but less saturated violet from primary colours which process is most suitable?

Correct answer: Mix red and blue then add a small amount of yellow

The governing concept combines hue formation with saturation control. Red and blue first produce violet. Yellow is approximately complementary to violet in the traditional pigment wheel, so a small amount can neutralise or desaturate it; using only a little avoids turning the mixture muddy. White would lighten rather than darken the colour, and red plus yellow produces orange. Thus option A is correct.