In lye-based relaxers, what is the role of sodium hydroxide?

• A. Acts as a strong acid to soften hair.
• B. Only raises cuticle pH without chemically altering bonds.
• C. Protects scalp by neutralizing before processing.
• D. Sodium hydroxide acts as a strong base reducing disulfide bonds and creating high pH to soften and relax hair; neutralization re-stabilizes.

Answer: (D)