63. Health officials estimate that 35 million Africans are in danger of contracting trypanosomiasis, or "African sleeping sickness," a parasitic disease spread by the bites of tsetse flies.

(A)  are in danger of contracting（习语）

(B)  are in danger to contract

(C)  have a danger of contracting

(D)  are endangered by contraction

(E)   have a danger that they will contract

1．习语： be in danger of sth. 一级排除B,D,E

2． 时态：二级排除C

现在完成时没有理由，而且从逻辑意思上看 have a danger 也不对。

the passive construction in D would be unnecessarily wordy and also imprecise, because it is the disease more than the act of contracting it that poses the danger.(意思表达的细微差别) èbe endangered by的意思也有区别, 往往表示环境/野生动物被endangered