If green is excessive while making yellow-green, toward which colour will the result shift?

Correct answer: Toward green

The governing concept is colour bias in a mixture. Yellow-green is made from yellow and green, so the final appearance depends on the relative amount of each component. If green is present in excess, its hue becomes dominant and the result shifts toward green. It would move toward yellow only when yellow had the larger influence. Red and violet are not the named components, so option A is correct.