This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Organ Transplant / Graft, Subject name: Pathology
Method of prevention of GVHD in bone marrow transplantation is: 
Select and explain. 
A. T-cell removal, B. Prior immune suppression, C. Post procedure immune suppression, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: The following are the steps taken to reduce the risk of graft versus host disease: Getting the best donor match: donor is as closely matched to recipient with the technique of tissue typing. Use of immunosuppressive drugs like ciclosporin, tacrolimus etc T cell depletion: Removal of T cells from the donor's bone marrow is called as T cell depletion. Post procedure immune suppression using the drugs like methotrexate and cyclophosphamide.