Answer:
A. the secondary structure, tertiary structure and final shape
Explanation:
When a protein is denatured, secondary and tertiary structures are altered and affected but the peptide bonds of the primary structure (which is basically the initial shape of the protein) between the amino acids are left intact. Since all the structural levels of the protein take part into the determination of the protein's function, the protein can no longer function after it has been denatured.
