Sentence Correction

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

A

That parallelism ....

My take is A. maintains parallelism, has non essential modifier/appositive modifier in the commas that can be removed and still preserves the meaning of the sentence.

B - Awkward construction
C - "THEY" ambiguous, refers to "magnetic fields" or "surveillance system"
D. - Incorrect modifier
E. - use of "That" is incorrect, instead "SUCH" should be used. Not parallel also.

//ism----A

IMO A

SYNTAX USED:
of which type there are 200,000 worldwide, can interfere --MODIFIER

Researchers have announced that the magnetic fields emitted by one manufacturer's
security surveillance system can interfere
with pacemakers and that this interaction can bring on missed or irregular heartbeats,
nausea, breathlessness, dizziness, and even fainting.

Even without the modifier,the sentence makes sense..

A - scientists made two announcements, hence THAT need to be used. Only A qualifies.