Decreasing order of -I effect of the triad `[-NO_(2),overset(o+)(N)H_(3),-CN]` is
A. `-overset(o+)(N)H_(3)gt -NO_(2) tgt -CN`
B. `-overset(o+)(N)H_(3) gt -CN gt -NO_(2)`
C. `-CN gt - NO_(2) gt overset(o+)(N)H_(3)`
D. `-NO_(2) gt -CNgt overset(o+)(N)H_(3)`