Polylysine is a random coil when the pH is less than 11,while it forms an a-helix if the pH is raised to greater than 12.What happens at pH 12 to account for this?

A)The lysine residues are negatively charged,which electrostatically stabilizes the helix.
B)The positive charges on the lysine residues stabilize the a-helix.
C)The lysine residues are neutral,which eliminates electrostatic repulsion between the R groups.
D)The high concentration of OH⁻ ions in solution reduces the electrostatic repulsion between the R groups.