In the following pairs, identify the pair having a different (n+l) value?

The correct option is C 4s, 3d

$(n+l)$ value for $4s=(4+0)=4,3p=(3+1)=4,3d=(3+2)=5,4p=(4+1)=5,4d=(4+2)=6,5p=(5+1)=6$

Hence correct option is $4s,3d$ i.e., option C.