What change occurs when the amount of red is increased in an orange mixture?

Correct answer: The colour becomes reddish

Orange is formed from red and yellow pigments. Increasing the red proportion gives red a stronger influence, so the orange shifts toward a reddish orange. Option B is correct. Increasing yellow instead would make the mixture more yellowish. Green and violet are different secondary colours formed from different pairs of primary colours, so they do not follow from merely adding more red to orange.