A 52-year-old man with melanoma receives immunotherapy education. His oncologist explains that tumor mutations produce abnormal proteins synthesized within melanoma cells. These proteins are degraded by proteasomes in the cytoplasm into peptide fragments. The resulting peptides are transported into the endoplasmic reticulum, where they bind to newly assembled surface molecules. Once displayed on the tumor cell surface, these peptide complexes are recognized by CD8+ cytotoxic T lymphocytes, which kill the tumor cells.
Which of the following molecules on the melanoma cell surface presents these endogenously-derived tumor peptides to CD8+ T cells?