各位大牛看看这个语法题怎么理解

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

根据gmat语法的要求 THAT 必须加   于是马上选择A  但是答案是D

这种题目和一般我们复习的语法有违背啊！！！ 很郁闷！！！

能不能告诉这个题的出处啊!

应该是A吧，D是fragment啊。

而且announced后面有跟that,所以应该引导从句，而非宾语。有annouce something的说法，但这里只能说announce that something does something.

http://gmatclub.com/forum/11-p505445

这上面说答案错了, 应该选A~