The Failure of Cytotoxic T Cells to Eliminate Tumors Can

The failure of cytotoxic T cells to eliminate tumors can be attributed to

A) failure of tumor antigen presentation.
B) failure of activation of tumor-specific T cells.
C) failure of recruitment of T cells to the tumor.
D) failure of the T cells to produce cytotoxic effector molecules.
E) All of the answers are correct.