The correct option is
D Quaternary structure
Proteins mostly prefers three dimensional tertiary structure. The tertiary structure provides the easy attachment to the cofactors which ultimately helps to enhance the catalytic activity of the enzyme. The tertiary structure is the three dimensional conformation of proteins. The folded peptide chain are stabilized by chemical bonds. Hydrogen bond, ionic bond, disulphide linkage and hydrophobic interaction stabilizes the structure.
Some of the proteins like keratin has secondary structure which is stabilized by the hydrogen bonds.
Some of the protein has primary structure where one amino acid is attached to the other with the peptide bond forming a linear chain.
So, the correct answer is option D.