Researchers have announced that the magnetic fields emitted by one manufacturer’s security surveillance 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.

1. of which type there are 200,000 worldwide, can interfere with pacemakers and that
2. of which, worldwide, there are 200,000 of that type, and which can interfere with pacemakers, and
3. of which type there are 200,000 worldwide, they can interfere with pacemakers and
4. 200,000 of which type exist worldwide, interfering with pacemakers, and
5. 200,000 of that type existing worldwide and can interfere with pacemakers, and

这道题目看得很晕，答案是D

后面的that宾语从句的主语是the magnetic fields and this interaction对么？NN来给分析一下吧。

肯定不是！选A

句子主干：

Researchers have announced that the magnetic fields can interfere with pacemakers and that this interaction can bring on heartbeats, nausea, breathlessness, dizziness, and even fainting.