How to tell whether an element is paramagnetic or diamagnetic?

If it has some unpaired electrons, then it would be PARAMAGNETIC whereas if it has all paired electrons, then it would be DIAMAGNETIC.

First to write electronic configuration.
Then Draw the valence orbitals
After that Look for unpaired electrons.
If one or more electrons unpaired then its paraamagnetic , if  all electrons are paired then its diamagnetic.

D. is the answer hope that you