The correct option is D Both Assertion and reason are true, and the reason is the correct explanation of the assertion.
We know that, in diffraction pattern, the central has the maximum intensity (I0) and intensity starts decreasing rapidly.
Intensity of first maximum is approximately (I022)
Intensity of second maximum is approximately (I062).
In interference pattern, almost all the bright fringes including central bright fringe will be at the same intensity.
So, If a person wants to observe sharp and clear fringes of good contrast, then, interference experiment is preferable compared to diffraction.
Hence, option (A) is correct.