When red-orange is lightened, what happens to its basic hue family?

Correct answer: It remains red-orange

The governing concept is the difference between hue and value. Hue identifies the colour family, while lightening changes value by adding white or increasing brightness; it does not automatically change red-orange into another hue category. Thus option A is correct: it becomes a lighter tint of red-orange. Blue-green, violet and a primary colour would require a different hue or mixing relationship, not merely lightening.