Which of the following configuration is expected to have max different in second and third ionization energy :

Question

$ (a)\;(1S)^2(2S)^2(2P)^2 \\(b)\;(1S)^2(2S)^2(2P)^6 \\ (c)\;(1S)^2(2S)^2(2P)^6(3S)^2 \\ (d)\;(1S)^2(2S)^2(2P)^1 $