What is the correct description of d electrons in a diamagnetic transition metal complex?

Question

What is the correct description of  d  electrons in a diamagnetic transition metal complex?

Answer

Only observed for TM complexes with two or more unpaired d electrons.

Answer

Only observed for TM complexes with one or more unpaired d electrons.

Answer

Only observed for TM complexes with a 'high-spin' configuration.

Answer

Only observed for TM complexes with zero unpaired d electrons.

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