In Young's double slit experiment, white light is used. The separation between the slits is b. The screen is at a distance d (d>> b) from the slits. Some wavelengths are missing exactly in front of one slit. These wavelengths are [IIT 1984; AIIMS 1995]

• A.            \[\lambda =\frac{{{b}^{2}}}{d}\]                                     
• B.            \[\lambda =\frac{2{{b}^{2}}}{d}\]
• C.            \[\lambda =\frac{{{b}^{2}}}{3d}\]                                   
• D.            \[\lambda =\frac{2{{b}^{2}}}{3d}\]