A mosquito bite can transmit to a person the parasite that causes malaria, and the use of mosquito nets over children's beds can significantly reduce the incidence of malarial infection for children in areas where malaria is common. Yet public health officials are reluctant to recommend the use of mosquito nets over children's beds in such areas.
Which of the following, if true, would provide the strongest grounds for the public health officials' reluctance?
题目说: the use of mosquito nets over children’s beds can significantly reduce the incidence of malarial infection for children in areas where malaria is common.就已经说明蚊帐是对减少malarial的发生有用的,那么官员在不愿意用蚊帐就不会是因为他防不了蚊子了··这样就反对了题目的条件 ------还有题目也没有说蚊帐可以防蚊子也只能说是一个常识,那么C答案就无关了·