What Maintains the Secondary Structure of a Protein

What maintains the secondary structure of a protein?

A) peptide bonds between adjacent amino acids
B) hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
C) disulfide bonds between the amino group of one peptide bond and the R group of another amino acid
D) hydrogen bonds between the carboxyl group of one peptide bond and the R group of another amino acid