E seems better

I think proton-induced x-ray emission is the subject of the sentence, E puts it in the right place!

I was stuck between A and C but I go with C...


The way I saw it was this...removes all the words between the first comma and the last phrase:

For 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, is finding uses in medicine, archaeology, and criminology.

For 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, is finding uses in medicine, archaeology, and criminology.

So the reason I chose C is because the subject ("the technique") is clearly what "is finding uses medicine, archaeology and criminology.

Of course I could be wrong...Any reason why I am absolutely wrong will be greatly appreciated!
_________________

"No! Try not. Do. Or do not. There is no try.

(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,
- it seems developement is finding use in medicine instead of the technique by placing 'originally developed for detecting air pollutants' at the front of the sentece.

(B) Originally 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
- Same with A

(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,
- I'll go with this one. originally developed now points to technique, the modifier for the tehcnique, introduced by 'which' is modifying the technique correctly.

(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 substance quickly and without destroying it,
- 'has the ability is wrong'. A technique does not have ability, it only posses capability.

(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,
- same with D

C it is.

need you help here. for the pronouns "it" in the underlined portion, does it refer to substance or elements.

I am kind of confused on the application of singular pronouns when there are multiple s-v nouns presented. Does the usage of "it" here make the reference confusing or does the co-existence of singular and plural nouns solve that problem?

Thanks.

OA is A and no the qtn is not from OG