The correct answer is (A): Have good π-accepting character
Ligands like :CO, are sigma donor and π-acceptor and they make stronger bond with lower oxidation state metal ion, in this case back bonding is more effective.
Oxidation is a chemical process which can be explained by following four point of views
In terms of oxygen transfer
In terms of electron transfer
In terms of hydrogen transfer
In terms of oxidation number
Oxidation in Terms of Oxygen Transfer – Oxidation is gain of oxygen.
Reduction is a chemical process which can be explained by following four point of views
In terms of oxygen transfer
In terms of electron transfer
In terms of hydrogen transfer
In terms of oxidation number
Reduction in Terms of Oxygen Transfer – Reduction is loss of oxygen.
A chemical reaction which involves transfer of electrons or change in oxidation number of atoms is called redox reaction.