Dear dvinoth86

Here's what I am going to say. I don't know the source of this question. Not all GMAT prep questions are created equal. The SC questions that appears on the GMAT itself are gems, absolutely superb in their clarity and polish, and some test prep sources produce SC questions of comparably high quality. Other GMAT prep sources, to be honest, produce junk SC.

Let's say, I have my suspicions about this question. This is not a question that would appear on the real GMAT. Here's the sentence with the least offensive answer, (D):

The study, called the National Lung Screening Trial, focused on a specific high‐risk group: 53,000 current and former heavy smokers, aged 55 to 74, who had smoked for at least 30 pack‐years.

Yes, you are correct --- the modifier touch rule requires the modifier ("who had smoked ...") to touch the noun it modifies ("smokers"). This sentence does not do that, and so is less than ideal. Is it out-and-out incorrect? That's a matter of debate.

A vital modifier can intervene between a modifier and its target. See this post for more on that idea:
http://magoosh.com/gmat/2012/gmat-gramm ... modifiers/
Here, the intervening phrase "aged 55 to 74" is clearly not vital. It is set off by commas, which is the hallmark of a non-vital modifier. No clear rule justifies its position between the noun and the modifier.
At the same time, it's very short, and putting it there involves absolutely no ambiguity --- that's not a resounding vote of support, but some folks would argue on that basis that it's correct. Admittedly, there is not universal consensus on the grammar of this particular point.

One further piece of support is that --- any attempt to reword the sentence to eliminate this problem makes the sentence longer and more awkward. For example:
The study, called the National Lung Screening Trial, focused on a specific high‐risk group: 53,000 current and former heavy smokers, who were aged 55 to 74 and had smoked for at least 30 pack‐years.
Hardly a model sentence. There is no good way to rework (D) as it stands, which is another sorta argument in its favor.

Mathematics this ain't!!! I'm sorry I can't give you a more definitive answer. On the real GMAT, correct answers will be 100% correct (though not necessary ideal), and incorrect answers will be wrong. On this question, the best answer is in a gray zone ---- not something you will encounter on the real GMAT.

Moral: don't accord the same degree of trust in each and every practice question you see. Some practice questions sources are of much higher quality, and others don't hold up the standard. If you want some high quality questions, follow the link in the signature of the post.

Let me know if you have any further questions.

Mike
_________________

Mike McGarry
Magoosh Test Prep

hello
here goes my analysis
this question is about testing pronoums
and mainly which that who
the original choice is wrong , as smokers are people hence which can not be used
A is wrong
since we have both former and current smoker the choice of the simple past is impossible
simple past means that an action is over , completed and finished . we can eliminate c

hence we are left with BDE
E is wrong because the use of "were aged "means that the smoker age a long time ago :they were aged 55 to 74
this change the meaning
the higher at least is confusing so
the 2 left choice are B and D
B use that
D use who use to represent a subject

I will go For D

HOPE this help
best regards

Why, thank you. That means a lot to me. Thank you very much.

Mike
_________________

Mike McGarry
Magoosh Test Prep