Which mixture is more likely to produce a cleaner and brighter orange?

Correct answer: Yellowish red and reddish yellow

The governing concept is pigment bias in subtractive colour mixing. A yellowish red and a reddish yellow are both close to orange, so they contain less of the complementary blue-green influence that would dull the mixture. Bluish red and greenish yellow introduce more opposing components, red and blue tend toward violet, and yellow with violet partially neutralises. Thus option D is the cleanest likely orange.