Tertiary colours

Correct answer: A. Add a small amount of dark red

Explanation: To lower value while preserving the hue family, add a compatible dark red in a small amount and test gradually. Blue-green is complementary and can neutralize the red-orange, reducing saturation; grey also dulls it, while white lightens rather than darkens it. Thus option A is the most suitable controlled adjustment.

Correct answer: D. Yellow-green

Explanation: The governing concept is approximate complementarity on a twelve-part colour wheel. Red-violet is located near the magenta-violet region; moving about six positions across the wheel reaches yellow-green. These two hues therefore create a strong visual contrast. Red-orange and yellow-orange remain on the warm side, while blue-violet is close to red-violet rather than opposite it. Hence, option D is correct.

Correct answer: B. Red-violet

Explanation: The governing concept is complementary contrast on the colour wheel. Yellow-green lies approximately opposite red-violet, so these two hues have strongly contrasting colour influences. Blue-green is nearby and therefore analogous rather than opposite; yellow-orange and red-orange are also on the warmer side and are not the complementary counterpart. Thus red-violet in option B provides the strongest contrast in this set.

Correct answer: C. Add a small amount of grey

Explanation: The governing concept is the difference between hue and intensity or saturation. Adding a small amount of neutral grey reduces the vividness of blue-green while keeping it recognisable as a blue-green hue. White mainly raises value and can make the colour lighter; adding blue changes the balance, and yellow-orange introduces another hue. Therefore option C best meets both requirements.