152. When the technique known as gene-splicing was invented in the early 1970's, it was feared that scien­tists might inadvertently create an "Andromeda strain," a microbe never before seen on Earth that might escape from the laboratory and it would kill vast numbers of humans who would have no natural defenses against it.

(A) it would kill vast numbers of humans who would have no natural defenses against it

(B) it might kill vast numbers of humans with no natural defenses against it

(C) kill vast numbers of humans who would have no natural defenses against it(虚拟语气没有错)

(D) kill vast numbers of humans who have no natu­ral defenses against them

(E) kill vast numbers of humans with no natural defenses against them

请问：DE除了them使用错误以外还有别的错误吗？D中who引导的是限制型定语从句还是非限制性定语从句？

E改成kill vast numbers of humans with no natural defenses against it对吗？

我觉得E这样改不好，因为 with是伴随状况，这里应该是修饰humans的，应该用从句比较好。

D 中还有是have 的错误，应该用would have 因为前面是might，全句都是过去时态.

偶有一个问题，不考虑would的因素，请问with引导的修饰结构和who引导的修饰结构有什么区别么？谢谢