The color of wavelengths that shown at color 1 is (A). Red light.
Hi ! Here, I will help you to explain about the refraction of light. When a visible light is bent by water droplets or a prism lens, it will undergo refraction. Refraction will cause light that appears chromatic to be divided into seven spectra, namely: red, orange, yellow, green, blue, indigo, and purple. The order has been ordered from the wavelength, and the red color has the longest wavelength so that it is located at the top and looks the most curved.
Based on the image, the part of the light that will come out of "number one" is the red light. In accordance with the initial agreement, that red has the longest wavelength. With this feature, red is very easy to bend to "overshadow" the color spectrum with shorter wavelengths. As a comparison :
The color of wavelengths that shown at color 1 is (A). Red light.