The correct answer is D. The wavelength of electrons is smaller as compared to the wavelength of visible light.
The wavelength of a wave is the distance between two consecutive crests or troughs. The shorter the wavelength, the higher the resolution of the image. Electrons have a much shorter wavelength than visible light, which allows them to produce images with much higher resolution.
Option A is incorrect because the power of a lens does not affect its ability to resolve detail.
Option B is incorrect because the velocity of electrons does not affect their wavelength.
Option C is incorrect because the energy of electrons does not affect their wavelength.