[A] A substance derived from the Madagascar periwinkle, which has proved useful in decreasing mortality among young leukemia patients,

**A derivative, which has proved useful in decreasing mortality among young leukemia patients, of the Madagascar periwinkle,**

[C] A Madagascar periwinkle derivative, which has proved useful in decreasing mortality among young leukemia patients,

[D] The Madagascar periwinkle has a derivative which has proved useful in decreasing mortality among young leukemia patients, that

[E] The Madagascar periwinkle, a derivative of which has proved useful in decreasing mortality among young leukemia patients,

[C] A Madagascar periwinkle derivative, which has proved useful in decreasing mortality among young leukemia patients,

[D] The Madagascar periwinkle has a derivative which has proved useful in decreasing mortality among young leukemia patients, that

[E] The Madagascar periwinkle, a derivative of which has proved useful in decreasing mortality among young leukemia patients,