Researchers have announced that the magnetic fields emitted by one

A for me


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 -> awkward construction
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

Good one!

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 [ of which and that type – redundant + “which” incorrectly modifies type – eliminate it]
C. of which type there are 200,000 worldwide, they can interfere with pacemakers and [“they” can not refer to Singular manufacturer’s security surveillance system – eliminate it]
D. 200,000 of which type exist worldwide, interfering with pacemakers, and [ 200,000 of which type is awkward + interfering and can bring is not parallel to can bring – eliminate it]
E. 200,000 of that type existing worldwide and can interfere with pacemakers, and [“and” incorrectly coordinates with main clause – eliminate it]

Answer: A

Lets eliminate Wrong options .A is good but ;lets explore for a better option

B ->of which and of that are redundant -> ELIMINATE
C->they can is wrong since does not continue the previous sentence
D->interfering is not paralel with interaction can
E->too many ands is never good .Also existing worldwide and can interfere is not correct
A -> is perfect

IMO A

OA- D

No its not GMATPrep. What I read in various forums is GMAT Sets are retired GMAT Tests.
https://www.manhattangmat.com/forums/gma ... t3757.html

good question. Bumping up for more review

Indeed a good Question would love to review this one...

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 - Correct

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

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

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

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

Hence IMHO (A) is the best...

whenever you are looking at such long sentences, always look if your Subject has a VERB by hiding everything else..
lets see C
Researchers have announced that the magnetic field emitted by one brand of security surveillance system, of which type there are 200.000 worldwide, they can interfere with pacemakers and this interaction can bring on missed or irregular heartbeats,nausea and even fainting. ---- NO verb

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

Straight A

Merged topics. Please, search before posting questions!

Parallelism issue; Researchers have announced THAT the magnetic fields....and THAT.

Only A does that.

That AND That,,,,only A does it,,,,
all other options have missing S-V

Well i would apply the parallelism technique as explained by GMATNinja ,

First lets see if there is any parallelism trigger such as or,but, and (its the most common seen on the GMAT)

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.

As we could see from the above sentence their is the "and" word.

Now we need to check the Stem of the sentence which is "Researchers have announced" .

Lets construct the sentences before the parallelism trigger and after the parallelism trigger and compare:

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 --(1)

Researchers have announced that this interaction(Magnetic fields with the pacemaker) can bring on missed or irregular heartbeats, nausea, breathlessness, dizziness, and even fainting. --(2)


The only option that makes sense is Option A.

Hope the above explanation helps.

If your new to the whole parallelism concept or want to get a better picture of the following concept please refer to the below video link which i found immensely useful:

https://www.youtube.com/watch?v=vQgATaaw1ok

Could you please, explain what the exact problem is in:
D. 200,000 of which type exist worldwide
E. 200,000 of that type existing worldwide
to these fragments sounds good...

This question is based on Parallelism and Construction.

This sentence states that researchers have announced two negative effects of one manufacturer’s security surveillance system. The verb ‘announced’ is generally followed by a clause that begins with the relative pronoun ‘that’. Since in this sentence, there are two effects, there should be two clauses beginning with ‘that’.

Option A maintains the parallelism and also contains an appropriately placed modifier - of which type there are 200,000 worldwide – that modifies the “security surveillance system”. So, A is the best of all the options.

In Option B, the second relative pronoun ‘that’ is redundant. Since the relative pronoun ‘which’ is already mentioned, there is no need for another pronoun to refer to “security surveillance system”. This option is also wordy because of the repeated pronoun ‘which’. By leaving out the requisite pronoun ‘that’, the option does not maintain parallelism.

In Option C, the pronoun ‘they’ is redundant. The pronoun ‘which’ already refers to “security surveillance system”, so there is no need for another pronoun. So, Option C can be ruled out.

Option D lacks parallelism because there is no relative pronoun to clarify that the last part of the sentence presents another effect of the security surveillance system. The participle ‘interfering’ also makes the construction of the sentence clumsy. So, Option D can be eliminated.

Option E implies that 200,000 of the type existing is one of the qualities of the security surveillance system. There is also a complete lack of parallelism in the sentence. So, Option E can be eliminated.

Therefore, A is the most appropriate option.

Jayanthi Kumar.

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