+1 D (I am not too happy, but this is the best I got)
Premise - Studies have demonstrated that many immigrants to the United States receive excellent scores on the mathematics portion of standardized college entrance examinations.
Conclusion - The high-quality mathematics education these people received in this country during their formative years is primarily responsible for this phenomenon.
Any options which weakens the conclusion is our answer
A. Immigrants who take standardized college entrance exams are not representative of the general population of immigrants, since only a small percentage of these people are college-bound.
(We are not talking about the whole population but those who take the examinations, it will make a good answer in case of an absence of any other better answer)B. Some educational experts are highly critical of the notion that standardized test scores can accurately indicate a student's level of college preparedness.
(Irrelevant)C. Average scores on standardized college entrance examinations have declined every year for the past two decades.
(Irrelevant)D. Because most immigrants are not native English speakers, their performance on the verbal portion of standardized college entrance exams is weak compared to that on the mathematics portion.
(This is our answer, the non-natives have a weak english and therefore they study maths more to get a competitive score, thus weakening the conclusion that the high-quality mathematics education these people received in this country during their formative years is primarily responsible for this phenomenon)E. Immigrants who arrived in the United States after the age of 18 score just as high on the mathematical portion of standardized tests as those arriving at a very young age.
(Irrelevant)Experts comment would be required
_________________
First Attempt 710 - https://gmatclub.com/forum/first-attempt-141273.html