If we interpret this question as "which colored light looks the brightest", then we can say that because of the sensitivity of our eyes, green will appear the brightest. This can be seen with different colored laser pointers, which generate beams of light at single wavelengths (visible light, light that is visible to our eyes, have different wavelengths that are measured in hundreds of nanometers). Our will perceive the green laser as the brightest one.

Because of the same eye perception, when we look at different colors (such as paint colors, clothes colors, etc) under the same intensity of white light, we also perceive a yellowish-green color as the brightest. Thank you!