[单项选择]

A large part of effective leadership is dependent on something called "style". But style is difficult to teach, and what makes one leader great and another mediocre is not easily defined. Leadership always implies power, and a broad definition in this context is that leadership includes the power to influence thoughts and actions of others in such a way that they achieve higher satisfaction and/or performance. Over the past century, there have been three major approaches to understanding leadership.
Identifying leadership traits, or the physical and psychological characteristics of leaders, was the first formal approach, and had a lot of intuitive appeal. It owed its origins to the mm of the century (about 1904) when trait studies began. At this time most American leaders came from certain wealthy families, the vast majority were white males, and there were some social norms about what leaders looked like (tall, square jaw, well groomed, etc.). The
A. better theories have since been developed
B. there were too many exceptions to the rule
C. it was found not to be the most important factor
D. it was not proved after World War II