我觉得答案有问题，哪位NN能帮忙解答一下这道语法题？谢了！

Researchers have announced that the magnetic fields emitted by one manufacture’s security surveillances system, of which type there are 200,000 worldwide, can interfere with pacemakers and that this interaction can bring on missed or irregular heartbeats, nausea, breathlessness, dizziness, and even fainting.

A.      of which type there are 200,000 worldwide, can interfere with pacemakers and that

B.      of which, worldwide, there are 200,000of that type, and which can interfere with pacemakers, and

C.      of which type there are 200,000 worldwide, they can interfere with pacemakers and

D.     200，000 of which type exist worldwide, interfering with pacemakers, and

E.      200,000of that type existing worldwide and can interfere with pacemakers, and

正确答案是D，可是困惑啊，D中interfering不能做谓语，那么and之前就不是一个完整的句子了，难道这也能成立吗？我觉得相比之下A似乎更好一些，虽然A的前半部分用了there be 句型，但是整个句子的结构是完整的。不知我的看法是否正确。

D 选项前半部分

200，000 of which type exist worldwide, 我理解是插入语,进一步解释system, 逗号后就应是谓语,interfering 显然不能做谓语呀. 应是错误的.

不知对不对.请指教.

Researchers have announced that the magnetic fields emitted by one manufacture’s security surveillances system, of which type there are 200,000 worldwide, can interfere with pacemakers and that this interaction can bring on missed or irregular heartbeats, nausea, breathlessness, dizziness, and even fainting.

A.      of which type there are 200,000 worldwide, can interfere with pacemakers and that

B.      of which, worldwide, there are 200,000of that type, and which can interfere with pacemakers, and

C.      of which type there are 200,000 worldwide, they can interfere with pacemakers and

D.     200，000 of which type exist worldwide, interfering with pacemakers, and

E.      200,000of that type existing worldwide and can interfere with pacemakers, and

如果是A则that引导两个宾语从句；

如果是D，则阴影部分the magnetic fields 和this interaction 是that引导的从句的主语。

虽然后可以，但我觉得，似乎A更好些。

不知道，A的主要错误在那里？

有道理啊，但仔细分析，以为从逻辑意义上好象不能将the magnetic field 与this interaction并列，因为本题”某种心脏监视仪中200，000台产品（相当于有问题的某一批号产品）产生了磁场，而这一磁场反过来影响心脏起博器，所以这一相互作用导致了不良结果“

所以　不能并列为主语，

即200，000 of which type exist worldwide不能认为相当于插入语结构，而只能当一分句

NN们请评判啊

个人觉得还是A好一些

D.     200，000 of which type exist worldwide, interfering with pacemakers, and

如果把interfering改为interfer就是很好的答案.

A中逻辑意思有问题.

我觉得这题出得有问题,或者是有人记错了

应该是A吧，如果是D， 句子就不完整了，没有the magnetic fields的谓语。

that's my two cents.

NN给指点指点