The correct option is C Magnifying power of red colour is more than the blue light.
The magnification for a light is inversely proportional to the focal length.
Since the focal length of violet light is the least, then its magnifying power will be the most. So, out of all options, the option (c) is the incorrect one which states that magnifying power of red colour is more than that of blue, as the focal length of a red colour is more than a blue colour.