Physics mcqWatch this thread
I'm not sure if I'm right but I think that single slit diffraction forms fewer fringes than the double-slit interference pattern. Also, since intensity is decreased, fewer fringes are observed as fringes appear darker.
A is also possible because if the intensity incident on the screen is assumed to be constant before and after the placement of the opaque film, the central fringe will appear brighter.
B is wrong as the central fringe will be twice the width of the other fringes. The outer fringes shouldn't change in width too.