The width is comparable to that of wavelength of light.

(b) different from a geometrical image.

(d) diffused coloured region around a sharp central white spot.

As we know phenomena of diffraction occurs when slit width is comparable to that of the wavelength which is being incident. And the wavelength of white is 380 nm (Violet) to 750 nm(Red) both

of which are of the order of the slit’s width. And due to diffraction phenomena, we will not be able to see geometrical image (Here geometrical image means the circular image of a pinhole).

And due to diffraction, a diffused central spot will be visible around a sharp central bright spot which will be a mixture of all colours. And we know a mixture of all colour will be white in nature.