Correct Answer - B
According to VSEPR theory, The order of repulsion of electrons is lp-lp repulsion gt lp-bp repulsion gt bp-bp repulsion Higher the number of lone pair of electrons (greater is repulsion ) lower is the bond angle and vice-versa. In `NO_2^-` one lone pair of electron is present while in `NO_2^+` no lone pair of electron is present. Hence the correct order of bond angles is `NO_2^(-) lt NO_2 lt NO_2^+`