Ricin Is One of the Newest Chemicals Used as a Nerve

Ricin is one of the newest chemicals used as a nerve agent.Which of the following are potential medical uses for ricin?

A) to prevent certain cancer cells and in bone marrow transplants
B) to kill cancer cells and in bone marrow transplants
C) in bone marrow transplants and to prevent certain cancer cells
D) to kill cancer cells and in renal transplants