Which one of the following molecules is expected to exhibit diamagnetic behaviour ?

The diamagnetic species have paired electrons are repelled by a magnetic field. While the paramagnetic species have unpaired electrons and are attracted towards the magnetic field.
Molecular orbital configuration of $C_2(6+6=12):{\sigma }_{1s}^2,{\sigma }_{1s}^{\ast 2},{\sigma }_{2s}^2,{\sigma }_{2s}^{\ast 2},{\pi }_{2p_x}^2={\pi }_{2p_y}^2$
Since, all the electrons are paired, it is a diamagnetic species.
Molecular orbital configuration of $N_2(7+7=14):{\sigma }_{1s}^2,{\sigma }_{1s}^{\ast 2},{\sigma }_{2s}^2,{\sigma }_{2s}^{\ast 2},{\pi }_{2p_x}^2={\pi }_{2p_y}^2{\sigma }_{2p_z}^2$
It is also diamagnetic species because all the electrons are paired.
Molecular orbital configuration of $O_2(8+8=16):{\sigma }_{1s}^2,{\sigma }_{1s}^{\ast 2},{\sigma }_{2s}^2,{\sigma }_{2s}^{\ast 2},{\sigma }_{2p_z}^2,{\pi }_{2p_x}^2={\pi }_{2p_y}^2,{\pi }_{2p_x}^{\ast 1}={\pi }_{2p_y}^{\ast 1}$
It is paramagnetic species because of the presence of unpaired electrons in the antibonding $\pi -$ orbitals.
Molecular orbital configuration of $S_2(16+16=32):LL{\sigma }_{3s}^2,{\sigma }_{3s}^{\ast 2},{\sigma }_{3p_z}^2,{\pi }_{3p_x}^2={\pi }_{3p_y}^2,{\pi }_{3p_x}^{\ast 1}={\pi }_{3p_y}^{\ast 1}$
It is paramagnetic species because of the presence of unpaired electrons in the antibonding $\pi -$ orbitals.
Hence, $C_2$ and $N_2$ molecules is expected to exhibit diamagnetic behaviour.