How can contrast be maintained in a palette with few colours?

Correct answer: By varying value, temperature, and saturation

The governing concept is contrast, which can come from more than hue alone. Even a small palette can show contrast through value differences such as light versus dark, temperature differences such as warm versus cool, and saturation differences such as vivid versus muted. Option A is correct. Identical colours remove contrast, erasing colours cannot build it, and paper texture alone is not colour contrast.