Which pair best represents warm and cool versions of the same basic colour?

Correct answer: Yellowish red and bluish red

The governing idea is colour bias within one hue. A red that leans toward yellow is a warm, yellowish red, whereas a red that leans toward blue is a cool, bluish red. Thus option D compares two temperature variations of the same basic colour, red. Yellow and violet or red-orange and blue-green are different hues, and black and white are neutrals rather than warm and cool versions of one hue.