C. Mandy could be kept in isolation until her body recognizes the donor’s stem cells as her own cells.
Explanation:
The best thing that is done after stem cell transplant is that the patient is kept in isolation till the time the patient's body recognizes the donor's stem cells as her own cells. The isolated environment must be sterile i.e. it must be free of pathogens. By doing this, the patient will not get infected from any disease even if her immune system is weak due to intake/injection of immunosuppressive drugs. Meanwhile, her body starts recognizing the donor's stem cells which were initially foreign to her own cells.
