Which colour is useful in a small amount to mute blue acrylic colour?

Correct answer: Orange

On the traditional colour wheel, orange is complementary to blue. Adding a very small amount of orange reduces the saturation or intensity of blue because the opposing hues partially neutralise each other. Option C is correct. White lightens blue and creates a tint, yellow shifts it toward green, and green does not provide the direct complementary contrast needed for controlled muting. Too much orange, however, can make the mixture dull or brownish.