Match List-I with List-II and choose the correct answer from the options given below.

List - I	List - II
(a) Protein	(i) C = C double bonds
(b) Unsaturated fatty acid	(ii) Phosphodiester bonds
(c) Nucleic acid	(iii) Glycosidic bonds
(d) Polysaccharide	(iv) Peptide bonds

To match each macromolecule in List‑I with the type of bond that links its building blocks in List‑II, we consider the characteristic linkage for each class.

1. Protein – Proteins are polymers of amino acids. Amino acids are joined by peptide bonds, which are formed between the –COOH group of one amino acid and the –NH₂ group of the next. In List‑II, peptide bonds correspond to (iv).

2. Unsaturated fatty acid – Unsaturated fatty acids contain one or more carbon–carbon double bonds (C=C) in the hydrocarbon chain. This type of bond is described as C = C double bonds, which is option (i) in List‑II.

3. Nucleic acid – Nucleic acids are polymers of nucleotides. Nucleotides are linked by phosphodiester bonds, where the phosphate group of one nucleotide connects to the 3’‑hydroxyl of the sugar of the next. This matches option (ii).

4. Polysaccharide – Polysaccharides are chains of monosaccharides joined by glycosidic bonds, which link the anomeric carbon of one sugar to a hydroxyl group of the adjoining sugar. In List‑II, glycosidic bonds are option (iii).

Putting these matches together gives the correct correspondence:

a – iv, b – i, c – ii, d – iii