Regarding secondary structure of proteins, correct statements are

A) It refers to shape of polypeptide chain

B) It arises due to regular folding of the backbone of polypeptide

C) It is stabilized by hydrogen bonding

D) Most common secondary structure of protein is $\mathrm{\beta }-$pleated structure

• A

  A, B, C, D

• B

  A, B, C only

• C

  A, C only

• D

  A, B only