If green becomes more yellow than required what should be added to balance it?

Correct answer: A little blue

The governing concept is component balance in a secondary colour. Green is produced from yellow and blue, so a green mixture that looks too yellow lacks sufficient blue in its proportion. Adding a small amount of blue moves the mixture toward a more balanced green. Red or orange introduces additional pigments that may dull or muddy the result, while white only lightens it without correcting the yellow-blue balance. Thus, option C is correct.