For most scientists, the period of highest creativity occurs before the age of forty. It is commonly thought that this happens because the aging process brings about a loss of creative capacity. However, it turns out that almost all scientists who produce highly creative work beyond the age of forty entered their field late, less than a dozen years before their creative breakthroughs. Since
creative breakthroughs by scientists under forty also generally occur within a dozen years of the scientist’s entry into the field, it is most likely that the real reason why scientists over forty rarely produce highly creative work is not that they are too old but rather that they generally have spent too long in a given field.
In the argument given, the two portions in boldface play which of the following roles?
A. The first presents a state of affairs, the explanation of which is at issue in the argument; the second provides evidence in support of the explanation that the argument seeks to establish.
B. The first presents a state of affairs, the explanation of which is at issue in the argument; the second presents evidence that has been used to challenge the explanation that the argument favors.
C. The first is the main conclusion of the argument; the second provides evidence in support of that main conclusion.
D. The first is a claim that the argument seeks to refute; the second provides evidence in support of an alternative claim that the argument seeks to establish.
E. The first is a generalization that, according to the argument, has exceptions; the second presents some of those exceptions.