The Gene PD- 1 Plays an Important Role in Immune

The gene PD- 1 plays an important role in immune response to tumor cells.How would using gene editing to knock out this gene help T cells recognize and kill cancer cells?

A) PD- 1 will be expressed in the cytosol of the T cell.This protects PD- 1 from cancer cells.
B) PD- 1 will be expressed in the cytosol of the cancer cell.This protects PD- 1 from the T cell.
C) PD- 1 will not be expressed on the cancer cell surface.This prevents T cell recognition.
D) PD- 1 will not be expressed on the T cell surface.This circumvents one line of the cancer cells defense.