【单选题】Listen to Passage 1 in "Listening in" and choose the best way to complete the sentence. The speaker believes it's possible that "Outliers" is __________.
A.
Gladwell's apology for his own success
B.
the result of 25 years in journalism
C.
not to be taken too seriously
D.
proof that Gladwell considers he's been as successful as Bill Gates, the Beatles, and others.