Which colour is useful for showing the warm effect of brick or fire?

Correct answer: Red-orange

Brick and fire are commonly associated with warm red and orange hues. Red-orange is a tertiary colour combining red and orange, so it can show heat, glow and a warm surface effect. Blue-green and blue-violet are cool colours, while yellow-green is generally linked with foliage or fresh natural tones. Hence, option B is the best answer.