Diffraction of light shows that light behaves like a wave. It involves the change in the direction of waves while passing through any obstacle. Diffracted light can produce fringes of light, dark or colored bands (Just like the rainbow which is also a light wave). Diffracted light has certain wavelength, amplitude , frequency and speed which are the basic characteristics of being a wave which shows that light actually behaves like a wave.
A concave lens can only form a virtual image. The correct option among all the options that are given in the question is the third option or option "C". Concave lenses are mostly thinner in the middle compared to its edges. I hope that this answer has come to your help.
