The molecular orbital configuration of the molecules given is 

Total no. of electrons in $NO$

$=7(N)+8(O)=15$ 

Hence $E.C.$ of $NO$

$KK{[\sigma 2s]^2}{[{\sigma ^*}(2s)]^2}{[\sigma 2{p_z}]^2}$ 

                           ${[\pi (2{p_x})]^2}[\pi {(2{p_y})^2}]{[{\pi ^*}(2{p_x})]^1}$

Due to presence of one unpaired electron

$NO$ is paramagnetic.

Except $NO$ all are diamagnetic dur to absence of unpaired electrons.