Read the following paragraphs and answer the question.
I’ve always been curious about people, and I’ve tried to learn what I could from them. Many times during long rides, I’d developed a rapport with my passengers—and quite often I’d received very good advice from accountants, lawyers, and plumbers. Maybe it was that this fellow clearly loved his work; maybe it was just the pleasant mood of a spring morning. But I decided to ask for his help. “Could I ask a big favor of you?” He didn’t answer. “I have a son，15, a good kid. He’s doing well in school. He wants a job. But a 15-year-old can’t get hired unless his old man knows someone who owns a business，and I don’t.” I paused. “Is there any possibility that you might get him some kind of a summer job— even if he doesn’t get paid?” He still wasn’t talking，and I was starting to feel foolish. Finally, at the airport, he said, “Well, the medical students have a summer research project. Maybe he could fit in. Have him send me his school record.” He scribbled something and paid me. It was the last time I ever saw him.
What was the narrator's impression of the doctor after some talking?（）
A.正确答案BHe was not very dependable.
B.He was happy with his job.
C.He was not very sociable.
D.He was kind and helpful.
