Which of the following is paramagnetic ?

CN-, CO and NO+ are isoelectronic with 14 electrons each and there is no unpaired electrons in the MO. configuration of these species. So these are diamagnetic; O2- is paramagnetic due to the presence of one unpaired electron.(CN-, CO, CO+)14 = σ1s2, σ*1s2, σ2s2, σ*2s2 π2py2=π2pz2 σ2px2  (No unpaired electron diamagnetic) O2-=σ1s2, σ*1s2, σ2s2, σ*2s2σ2px2 π2py2 = π2pz2, π*2py2=π*2pz1(One unpaired electron, paramagnetic)