Why is the study of warm and cool colours useful for an artist?

Correct answer: For showing mood, atmosphere, and depth

Option B is correct because warm and cool colours help an artist communicate mood, atmosphere, emphasis, and a sense of spatial depth. Warm colours may appear visually active or advancing, while cool colours can suggest calmness or distance, especially when the values and surrounding colours support that effect. Colour study is therefore useful for planning a composition, not merely for counting colours, choosing brushes, or cutting paper as suggested by options A, C, and D.