Why is the lysosomal degradation step crucial in the MHC class 2 antigen presentation pathway?

• A. It prevents the activation of cytotoxic T cells.
• B. It allows intracellular pathogens to be processed for MHC class 1 presentation.
• C. It facilitates the transport of peptides into the endoplasmic reticulum.
• D. It ensures that extracellular pathogens are broken down into peptides that can be presented by MHC class 2.

Answer: (D)