O2,Cu2+ and Fe3+ all have unpaired electrons so, they are paramagnetic,
O2hastwounpairedelectronsaccordingtoMOT,Cu2+hasd9configurationso,oneunpairedelectron.Fe+3hasd5configurationso,5unpairedelectrons.
∴ Weakly attracted by magnetic field.
NaCl and H2O does not have any unpaired electrons so they are diamagnetic,
∴ Weakly repelled by magnetic field.