If yellow-orange is removed from the colour wheel, the transition between which two colours will be interrupted?

Correct answer: Yellow and orange

On a standard twelve-part colour wheel, yellow-orange is the intermediate tertiary colour positioned between yellow and orange. It creates a gradual visual step from one neighbouring hue to the other. Removing it interrupts that specific progression, although the remaining colours still form a wheel. Red-violet belongs between red and violet, while blue-green belongs between blue and green. Therefore, option C is correct.