The Following Events Occur If Human Cells Expressing HLA- I

The following events occur if human cells expressing HLA- I are mixed with anti- HLA- I, complement, and trypan blue. What step indicates the cells are HLA- I?

A) Anti- HLA antibodies bind to HLAs on lymphocytes.
B) Trypan blue enters the cells.
C) Cells are damaged by complement.
D) Enzyme is released from neutrophils.
E) None of the answers are correct; the T cells are missing.