The H-Bonds Formed in the Tertiary Structure of Proteins Can

The H-bonds formed in the tertiary structure of proteins can be differentiated from those formed in secondary structures. What is the major distinguishing factor?

A) The H-bonds in 3^° structures are significantly stronger than those found in 2° structures.
B) The H-bonds in 3^° structures are more random than those formed in 2° structures.
C) The H-bonds in 3^° structures are formed by predictable interactions among the peptide backbone α-amine and α-carboxylate groups.
D) The H-bonds in 3^∘ structures are formed by interactions involving the side chain R-groups.
E) Both B and D are correct.