Which scheme is more suitable for making a narrow corridor appear visually wider?

Correct answer: Light cool blue and blue-green

Colour can influence the apparent depth and size of an interior space. Light cool hues such as pale blue and blue-green tend to recede visually, making walls seem farther apart and the corridor more open. Option C is therefore the best choice. Dark, highly warm, or strongly contrasting red-based schemes tend to advance or intensify surfaces, which can make a narrow passage feel more confined.