Which statement accurately defines protein denaturation and its effect on structural levels?

• A. Denaturation only affects membrane proteins and leaves soluble proteins unaffected; it is primarily a reversible phosphorylation-driven process.
• B. Denaturation alters a protein's secondary through quaternary structures (unfolding or aggregation) while leaving the primary amino acid sequence intact; common causes include heat, extreme pH, mechanical agitation, and salt concentration changes.
• C. Denaturation permanently removes amino acids from the primary sequence and selectively strengthens secondary and tertiary structures, typically caused by gentle temperature decreases.
• D. Denaturation converts proteins into nucleic acids by breaking peptide bonds and re-synthesizing bases, primarily due to exposure to ultraviolet light only.

Answer: (B)