Which colour pair is most suitable for producing a bright green?

Correct answer: Green-biased yellow and green-biased blue

The governing concept is subtractive colour mixing and colour bias. To make a bright green, choose a yellow and a blue that both lean toward green, because they contain less unwanted red or orange influence. Option B therefore gives the cleanest, strongest green. Reddish mixtures introduce the complement of green and make it duller, while red and blue do not produce green and orange-red with yellow moves away from the required hue.