GATE Electronics and Communications (EC) 2018 Solved Paper

Red (R), Green (G) and Blue (B) Light Emitting Diodes (LEDs) were fabricated using p-n junctions of three different inorganic semiconductors having different band-gaps. The built-in voltages of red, green and blue diodes are V_R, V_G and V_B, respectively. Assume donor and acceptor doping to be the same (N_A and N_D, respectively) in the p and n sides of all the three diodes.
Which one of the following relationships about the built-in voltages is TRUE?