In a Recent Experiment, NK Cells Were Collect from an MCMV

In a recent experiment, NK cells were collect from an MCMV infected mouse and placed into a healthy mouse.Upon exposure to the MCMV virus, the healthy mouse quickly mounted an immune response.How could these results BEST be interpreted?

A) MCMV virus failed to infect the healthy mouse.
B) NK cells show memory and are quickly able to recognize MCMV infected cells in the healthy mouse.
C) Plasma cells were transferred along with NK cells and produced antibodies that target MCMV virus particles.
D) T_C cells were transferred along with the NK cells and have been targeting MCMV virus particles.
E) T_H cells were transferred to the healthy mouse instead of NK cells and have stimulated B cells to activate.