A researcher needs to separate proteins based on both size and pH. Which technique should they use and why?

• A. NMR, because it provides structural information.
• B. 2D gel electrophoresis, because it separates proteins based on size and pH.
• C. Mass spectrometry, because it identifies proteins by mass-to-charge ratio.
• D. SDS-PAGE, because it separates proteins based on size.

Answer: (B)