White light is used to illuminate the two slits in a Young’s double slit experiment. The separation between the slits is b and the screen is at a distance d(>>b) from the slils. At a point on the screen directly in front of one of the slits. Certain wavelength are missing. Some of these missing wavelengths are

a) $\lambda =\frac{b^2}{d}$     b) $\lambda =\frac{2b^2}{d}$      c)$\lambda =\frac{b^2}{3d}$       d) $\lambda =\frac{2b^2}{3d}$