Which of the following is an example of cross-presentation?
A. An endogenous peptide being presented on MHC class I
B. An exogenous peptide being presented on MHC class I
C. An endogenous peptide being presented on MHC class II
D. An exogenous peptide being presented on MHC class II
E. A B-cell antigen being presented to a T cell
Answer: B