Which One of the Following Statements About the Structure of Proteins

Which one of the following statements about the structure of proteins is incorrect?

A) Hydrogen bonding stabilizes the $\alpha$ -helix proteins.
B) Nonpolar groups tend to face the outside of a protein in an aqueous solution.
C) Ionized amino acid side chains can form salt bridges within a protein.
D) Disulfide bonds provide strong intrachain interactions.
E) Heat can disrupt tertiary structure.