Which group contains only warm colours?

Correct answer: Red, yellow, orange

Red, yellow, and orange are commonly classified as warm colours on the colour wheel. They suggest sunlight, fire, heat, activity, and energy, so option A contains only warm colours. Option B contains only cool colours, while options C and D mix warm and cool colours. The classification describes a usual artistic convention; a particular shade may appear warmer or cooler depending on its neighbouring colours and context.