Sirolimus (Rapamune),a Relatively New Immunosuppressant,is Especially Helpful Following Kidney Transplants

Sirolimus (Rapamune) ,a relatively new immunosuppressant,is especially helpful following kidney transplants because:

A) it causes sodium retention.
B) it increases renin release from the kidneys.
C) it does not reduce glomerular filtration and other aspects of kidney function.
D) all of the above
E) none of the above