Originally developed for directing air pollutants, a technique called proton-induced X-ray emission, which can quickly analyze the chemical elements in almost any substance without destorying it, is finding uses in medicine, archaelogy, and criminology.

(A) Originally developed for detecting air pollutants, a technique called proton-induced X-ray emission, which can quickly analyze the chemical elements in almost any substance without destroying it,
(B) Orignially developed for detecting air pollutants, having the ability to analyze the chemical elements in almost any substance without destroying it, a technique called proton-induced X-ray emission
(C) A technique originally developed for detecting air pollutants, called proton-induced X-ray emission, which can quickly analyze the chemical elements in almost any substance without destroying it
(D) A technique originally developed for detecting air pollutants, called proton-induced X-ray emission, which has the ability to analyze the chemical elements in almost any
(E) A technique that was originally developed for detecting air pollutants and has the ability to analyze the chemical elements in almost any substance quickly and without destroying the substance, called proton-induced X-ray emission,

The correct answer is (A) OG explanation - The choice (A) successfully avoids the problem that may occur in the a long sentence with multiple modifiers. Also the non-restrictive clause which...destroying it is correctly placed after emission.

My question - In choice (A) Aint the non-restrictive clause is actually a relative clause introduced by 'which' and it modifies the word preceded the relative pronoun and in this case 'emission'?

The problem is in the explanation of other answer choices (C) & (D) OG says the relative clause introduced by 'which' is incorrectly and illogically modifies 'emission'?

I smell contradictions in the explanation. Can someone shed some light?

Thanks

I can see what you're saying here, but nouns that are modified by prepositional phrases can still be the referent of 'which' even if they are a few words distant from it.
This usually happens when the immediately preceding noun is grammatically incompatible with the verb after "which".

For example: "The picture of my brothers, which was taken last year in Mexico, is one of my favorites."

You might object to this sentence on the grounds that 'which' might be taken to modify 'brothers'. And, in a strict sort of way, you'd be right. But here's the catch: There's really no other reasonable way to write this sentence. You just can't get 'picture' next to the 'which' clause without creating total nonsense, or splitting the sentence into 2 smaller sentence-ettes.
plus, 'brothers' is plural, and is incompatible with 'which WAS'.

This is an interesting point, though, and subtle at that. I believe that we are working on getting it into our forthcoming strategy guide.

What is the problem with choice C? Why A is better than C

Thanks
Aishwary

The difference is in the placement of the various phrases.

A: "(opening modifier), (noun) (modified by necessary descriptive phrase), which" - in this structure, which refers to the noun. Note that the few words right after "technique" are simply the name of that technique. These words ("technique called proton-induced X-ray emission") collectively make up the extended noun phrase to which "which" refers. The single-word noun is technique but the other words are necessary to understand what technique we're talking about.

C: "(Noun) (modifier), (modifer), which" - in this structure, we've separated what had been the necessary descriptive phrase from the noun, so it is no longer a part of any extended noun phrase. As a result, the "which" in this case really does only apply to "emission" rather than to a "technique called emission" b/c "a technique called emission" as a simple noun phrase, is no longer part of the sentence.

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