If All of the Cysteine Residues of a Protein Were

If all of the cysteine residues of a protein were changed to threonines,what would happen to the protein structure?

A) Nothing would change because both residues have hydrophobic properties.
B) The structure would remain the same but the protein would lose activity.
C) The primary structure would be compromised because the protein would lose peptide bond formation.
D) The tertiary structure of the protein would be affected because it would lose disulfide bond formation.
E) The hydrogen bonds would be lost,affecting alpha and beta sheet formation.