What is formed when white is added to red-orange?

Correct answer: A tint of red-orange

The governing concept is the change in value produced by adding a neutral colour. White lightens the original hue and creates a tint, so adding white to red-orange forms a red-orange tint; option A is correct. A shade is made by adding black, not white. The mixture does not become a complementary colour or pure red, because its original hue remains red-orange while only its lightness changes.