Which of the sentences below expresses the essential information in the italic sentence in paragraph 3

A. In spite of certain characteristics that first-borns possess, many of them become leaders

B. An interesting fact that is difficult to explain is that many first-borns have served in high government positions.

C. Because first-borns tend to be very assertive, they are uncomfortable serving in government positions

D. Several examples support the idea that first-borns have characteristics that make them leaders