Answer:
C) tertiary structure.
Step-by-step explanation:
The tertiary structure of the protein refers to the overall three-dimensional structure and shape of individual polypeptide chains of a protein. The tertiary structure of a protein depends on four main types of interactions between the side chains (R) groups of the amino acid of a polypeptide chain.
The side chains of amino acids of a polypeptide chain can form weak interactions such as hydrogen bonds, hydrophobic interactions, ionic bonds, and the strong covalent bonds.
These interactions between the side chains of the constituent amino acids allow the distantly located amino acids (that may be present in different types of secondary structures) to interact within a completely folded configuration of a protein.