A certain tropical island received food donations in the form of powdered

milk for distribution to its poorest residents, who were thought to be

malnourished. Subsequently, the rate of liver cancers among those islanders

increased sharply. The donated milk was probably to blame: recent

laboratory research on rats has shown that rats briefly exposed to the

substances aflatoxin tend to develop liver cancer when fed casein, a milk

protein. This result is relevant because       .

A.in the tropics, peanuts, a staple of these island residents, support a

mold growth that produces aflatoxin.

B.the liver is more sensitive to carcinogens, of which aflatoxin may be

one, than most other bodily organs.

C.casein is not the only protein contained in milk.

D.powdered milk is the most appropriate form in which to send milk to a

tropical destination.

E.the people who were given the donated milk had been screened for their

ability to digest milk.