In a Young's double slit experiment 'd' distance between slit is $1 \times 10^{-4}\;m$ and $D=1\; m$. ( distance of screen from slits ) At a point P on the screen the resulting intensity is equal to the intensity due to individual slit $I_0$ The distance of P from central maxima when wavelength of $x=6000\;\mathring{A}$ is

Question

$(a)\;1\;mm \\ (b)\;2\;mm \\ (c)\;2.1\;cm \\ (d)\;1.2\;cm$