Which conclusion can be drawn from the experimental results described in the passage?
A. Compound 1 selectively sensitizes cancer cells to the chemotherapy action of Compound 2
B. Compound 1 sensitizes all cells to chemotherapeutic action
C. Compound 2 induces apoptosis in cancer cells only in conjunction with treatment with Compound 1
D. Compound 2 inhibits the NF-kB signaling pathway, which leads to apoptosis