$($A$)$ Draw Thickness of layer with index n$2=3\mathrm{.}6$ is $0\mathrm{.}52/3\mathrm{.}6/4=36\mathrm{.}2$nmThickness of layer with index $=$ n$3=2\mathrm{.}8$ is $0\mathrm{.}52/2\mathrm{.}8/4=46\mathrm{.}4($B$)$ see attached sheet and plot