The correct option is C Nickel - carbonic anhydrase
Proteins are biomolecules or polymers made up of amino acids. Proteins are chemically made up of C, H, O, N and S.
Amino acids are the basic units of protein and are made up of a basic amino group (−NH2), an acidic carboxyl group (−COOH), and an organic R group (or side chain) that is unique to each amino acid.
Cytochromes are redox-active proteins containing a heme, with a central Fe atom at its core, as a cofactor.
Chlorophyll a consists of a chlorin ring, whose four nitrogen atoms surround a central magnesium atom, and has several other attached side chains and a hydrocarbon tail.
Carbonic anhydrase is an enzyme that contains zinc and not nickel in its structure. It is involved in the reaction where CO2 reacts with water to form carbonic acid which further dissociate to form H+ and HCO3− ions.