Which one of the following electrons in the ground state will have least amount of energy?

Energy of electron depends on (n+l) values. 
H–atom n = 1; l=0 (n+l)=1+0=1 
An electron in hydrogen atom will have least amount of energy because value of n (principal quantum number) is least which is 1. 
(1) 2pe– in C–atom n=2; l=1 (n+l)=2+1=3 
(2) 4se– in Cu–atom n=4; l=0 (n+l)=4+0=4 
(3) outer most electron in Na n=3; l=0 (n+l)=3+0=3 to Na 
Energy order: 1s < 2p < 3s < 4s