The correct answer is (b).
When a beam of white light is allowed to fall on a prism, the light is refracted (bent) as it passes through the prism. The amount of refraction depends on the wavelength of the light. Shorter wavelengths of light, such as violet, are refracted more than longer wavelengths of light, such as red. This is why a rainbow is seen in the sky. The water droplets in the air act like prisms, and they refract the sunlight so that the different colors are separated.
The maximum deviation of the emerging light occurs for violet light because it has the shortest wavelength. The deviation of the light is also affected by the angle of incidence, which is the angle between the incoming light and the normal, which is an imaginary line perpendicular to the surface of the prism. The greater the angle of incidence, the greater the deviation of the light.
The other options are incorrect because they have longer wavelengths than violet light.