Which series shows the order by which an antigenic sequence of amino acids is brought in contact with a T-cell receptor by a major histocompatibility complex (MHC)?

A. Full-length protein --> MHC I --> MHC II --> T-cell receptor
B. Full-length protein --> MHC II --> MHC I --> T-cell receptor
C. Full-length protein --> free digested protein fragments --> MHC II --> T-cell receptor
D. Full-length protein --> free digested protein fragments --> MHC I --> free digested protein fragments --> T-cell receptor