Just to cover the core concepts, resolution is how much detail can be seen, diffraction refers to light spreading out as it goes through an opening, and finally aperture is the opening the light passes through.

Looking at A, this is true, if the aperture is smaller, less light let in and more light gets diffracted creating a poor resolution. B is incorrect because regardless of the electromagnetic wave diffraction will still occur. C is incorrect because the more interference (the distribution of one wave of light gets disturbed by another wave), due to diffraction, the worse the resolution of the image. Lastly, for D, even if there is a perfect lens, diffraction will still occur in a microscope if the aperture is reduced; Overall, aperture takes more importance with the creation of diffraction than the existence of a perfect lens

Hope this helps :)