Which type of violet is considered the coolest?

Correct answer: Blue-violet

The governing concept is colour bias within a colour family. Violet can lean toward red or toward blue; the stronger the blue component, the cooler the visual temperature normally becomes. Option C, blue-violet, is therefore the coolest choice. Red-violet and pinkish violet contain warmer red influence, while brownish violet is muted and earthy but is not the clearest blue-biased cool violet in this comparison.