Arrange the following steps in the presentation of antigens via Class II MHC:
- Antigen is phagocytosed by APCs.
- Antigen is processed into smaller peptides.
- Peptide-MHC II complex is formed.
- Peptide-MHC II complex is displayed on the cell surface.
1
1 → 2 → 3 → 4
2
2 → 1 → 4 → 3
3
3 → 4 → 2 → 1
4
4 → 3 → 2 → 1