Q ​As shown in the figure, a point light sourceis palced  at a distance 2f from a lens with focus length f, and a 
screen is placed  at 4f from the lens. The lens is then cut at the middle into two lower half. The upper half is moved upwards by a small distance d comparable to light wavelength and the  lower half is moved downwards by the distance d. What is pattern on the  screen? 
(A) Bright and dark stripes similar to the pattern seen in Young's double slit experiment 
E) Bright and dark concentric rings 
(C) Two large, bright, and partly overlapping patches 
(D)Two separate bright spots