Which tertiary colour contains primary yellow and secondary orange?

Correct answer: Yellow-orange

The governing concept is tertiary-colour formation on the colour wheel. A tertiary colour is produced by combining a primary colour with the adjacent secondary colour. Primary yellow combined with secondary orange gives yellow-orange, so option A is correct. Red-orange contains primary red and orange; yellow-green contains yellow and green; red-violet contains red and violet. The names of the components provide a direct way to check the answer.