The light that comes from the sun is called white light. Actually white light is a mixture of lights of different colors. When we look at the rainbow we can see the colors that make up the white light. This phenomenon, known as dispersion, occurs when a ray of composite light is refracted (refraction) in some medium, and its constituent colors are separated.
I attached you I picture where you can see this process
Basically, when the light passes through a glass prism, the different wavelengths that make up the beam of light travel inside it at different speeds and curl differently when entering and leaving resulting in a beam deviated from the initial direction and with its separate components.
When adding a solute to the solvent, the solution will then boil at a point much higher than the solvent itself. Therefore, it would take much longer for the solution to boil. Among the choices, the correct answer would be B. The water will boil at a higher temperature.