When do people decide whether or not they want to become friends? During their first four minutes together, according to a book（1）Dr. Leomard Zuninn. In his book, Contact: The First Four Minutes, he offers this advice to anyone（2）in starting new friendships: "Every time you meet someone in a social（3）, give him your undivided attention for four minutes. A lot of people's lives（4）change if you did just that."
You may have noticed that the（5）person does not give his undivided attention to someone he has just met. He keeps looking over the other person's shoulder, as if（6）to find someone more interesting in another part of the room. If（7）has ever done this to you, you probably did not like him very much.
When we are introduced to new people, the author suggested, we（8）try to appear friendly and（9）. In general, he says, "People like people who like（10）."
（9）下列正确的是（ ）

A.self-confident

B.self-confidence

C.self-confidently

D.self-confide