根据下面资料，回答1-20题
Science has now proved humans can't help talking about themselves. It just feels too good. In a new study, Harvard University researchers conducted a series of experiments to 1 how much people liked talking about themselves and why. In one study, they scanned people's brains 2 those people either revealed personal information about themselves or 3 the opinions of others. In another experiment, researchers tested whether people preferred to answer questions about themselves, other people or 4 facts—participants got differing levels of monetary compensation 5 on the question they chose.
No matter the test, the researchers found the results pointed the same way：humans get a biochemical excitement from 6 .
That's 7 we spend almost 40% of conversation talking about ourselves, says the study—our brain chemistry 8 us to do it. In the first experiment, researchers found that sharing personal information led to 9 in the reward areas of the brain—the same ones that are 10 in response to rewards like food. Talking about other people did not 11 the circuits as much. In the second experiment, people were willing to 12 17% of their earnings in order to answer questions about themselves. The researchers also noted that people 13 enjoyed self-disclosure if they knew other people were listening. When people were given a choice to share their responses with others or to keep them 14 , they sacrificed 25% of their potential earnings in order to 15 the personal information.
Previously, humans' 16 for talking about themselves was thought to be caused by a desire for 17 with others, a way to open up to people and get them to trust us 18 in hopes of setting the foundation for friendship. 19 this appears to be the first study to 20 that people talk about themselves mainly because they like the way it feels.
第（6）题选________

A self-talk

B self-disclosure

C self-confidence

D self-evaluation