another vote for D.
Historian: Newton developed mathematical concepts and techniques that are fundamental to modern calculus. Leibniz developed closely analogous concepts and techniques. It has traditionally been thought that these discoveries were independent. Researchers have, however, recently discovered notes of Leibniz’ that discuss one of Newton’s books on mathematics. Several scholars have argued that since the book includes a presentation of Newton’s calculus concepts and techniques, and since the notes were written before Leibniz’ own development of calculus concepts and techniques, it is virtually certain that the traditional view is false. A more cautious conclusion than this is called for, however. Leibniz’ notes are limited to early sections of Newton’s book, sections that precede the ones in which Newton’s calculus concepts and techniques are presented.
In the historian’s reasoning, the two boldfaced portions play which of the following roles?
A. The first provides evidence in support of the overall position that the historian defends; the second is evidence that has been used to support an opposing position.
B. The first provides evidence in support of the overall position that the historian defends; the second is that position.
C. The first provides evidence in support of an intermediate conclusion that is drawn to provide support for the overall position that the historian defends; the second provides evidence against that intermediate conclusion.
D. The first is evidence that has been used to support a conclusion that the historian criticizes; the second is evidence offered in support of the historian’s own position.
E. The first is evidence that has been used to support a conclusion that the historian criticizes; the second is further information that substantiates that evidence.
To solve CR questions, it is very essential to understand the argument and the arguer's(is arguer a correct word in english ??) stance/position.
Here in our question, the Historian starts out by giving us information that is traditionally believed to be true. Then he says that some people have found out Leibniz referred Newton's book in Leibniz' notes. So the scholars have concluded that the traditional belief is false and it was Newton who developed calculus and not Leibniz. The historian proceeds by giving us more info that Leibniz referred only certain portions of Newton's book that did not contain the calculus stuff.
The historian is defending the traditional belief here.
Choice A) The first does not provide the evidence of author's defense. This is opposite answer
Choice B) Same as above
Choice C) Cleverly worded answer choice. But it is out for the same reasons as A and B
Choice E) The option starts out correctly, first BF is what the author critizes but this option fails in the second half by saying that the second BF is the further evidence whereas it is actually counter-evidence.
That leaves us with option D which clearly tells what the 2 BF are.
"You have to find it. No one else can find it for you." - Bjorn Borg
Check out my GMAT blog - GMAT Tips and Strategies