阅读下列短文，从每题所给的四个选项（A、B、C、D）中，选出最佳选项。
【2016高考训练】
People have wondered for a long time how their personalities and behaviour are formed. It is not easy to explain why one person is intelligent and another is not, or why one is cooperative and another is competitive.
Social scientists are of course extremely interested in these types of questions. They want to explain why we possess certain characteristics and exhibit certain behaviour. There are no clear answers yet, but two distinct schools of thought on the matter have developed. As one might expect, the two approaches are very different from each other, and there is a great deal of debate between proponents of each theory. The controversy(争论) is often conveniently referred to as “nature and nurture”.
