Match the metals (column I) with the coordination compound(s)/enzyme(s) (column II):

We need to match the metals in Column I with their corresponding coordination complexes or enzymes in Column II.

Matching Analysis:

• (A) Cobalt ($$\text{Co}$$): The central metal atom present in Vitamin B12 (cyanocobalamin).
  $$\implies \text{(A)} \rightarrow \text{(iii)}$$
• (B) Zinc ($$\text{Zn}$$): The essential catalytic metal cofactor found at the active site of the enzyme carbonic anhydrase.
  $$\implies \text{(B)} \rightarrow \text{(iv)}$$
• (C) Rhodium ($$\text{Rh}$$): The central transition metal in Wilkinson's catalyst ($$[\text{RhCl}(\text{PPh}_3)_3]$$), used for alkene hydrogenation.
  $$\implies \text{(C)} \rightarrow \text{(i)}$$
• (D) Magnesium ($$\text{Mg}$$): The structural central metal ion coordinating the porphyrin ring in chlorophyll.
  $$\implies \text{(D)} \rightarrow \text{(ii)}$$

Conclusion:

Mapping each metal to its correct chemical framework gives the correct ordered pairing.

Answer: (A)-(iii); (B)-(iv); (C)-(i); (D)-(ii)