The _____ Secondary Structure Is Formed More Readily Than Other $\beta$

The _____ secondary structure is formed more readily than other types of secondary structures, most likely due to _____.

A) $\beta$ turn; hydrogen bonds with solvent molecules
B) $\beta$ sheet; R-group contacts
C) $\beta$ sheet; internal hydrogen bonds
D) $\alpha$ helix; R-group contacts
E) $\alpha$ helix; internal hydrogen helical bonds