Polymers are formed from their monomer units by the process of polymerization. Chemical bonds are formed between the monomers to hold them together in the polymer.
Lipids are the complex compounds that are formed by the joining of glycerol molecule and a fatty acid molecule. Therefore, option (a) is incorrect.
A carbohydrate is formed due to joining of its several monomer sub units of sugar molecules. Polysaccharides of carbohydrates are formed by the polymerization of many monosaccharide units. Therefore, option (b) is incorrect.
Nucleic acid is result of polymerization of several nucleotides. Each nucleotide is formed by the nitrogen base, phosphate and sugar. They do not result in the formation of proteins. Therefore, option (d) is incorrect.
Amino acids are the monomer units that are joined together by the formation of peptide bonds to form proteins. Therefore, polymerization of many amino acids produces proteins which are the essential building blocks of living organisms.
Hence, proteins are polymers that are formed from (c) amino acids.