In Young's double slit experiment parallel monochromatic light is incident on both the slits at an angle as shown in the figure. To obtain the central maxima at on the screen we can

Options

A. place a thin glass sheet of appropriate thickness in front of slit `S_(1)`.
B. place a thin glass sheet of appropriate thickness in front of slits `S_(2)`
C. submerge the whole experimental setup in appropriate liquid.
D. rotate the plane of slits by angle 6 anticlockwise

Answer

B