What is their attitude towards each other?

参考解析：

推理判断题。根据第三段“I moved his saucer and found his tip, along with a card：I am deeply grateful to you. The ... thanks to you. God bless you!”我移了他的盘子，发现了他给的小费，还有一张卡片：“我非常感激你。愿上帝保佑你！以及第四段“The night of my car accident, I was heading for an interview in an illegal dance club. Seeing human kindness through his heroic gesture turned my life around and brought faith back into my life. I said a silent prayer for him and got back to work, smiling.”车祸当晚，我正前往一家非法舞蹈俱乐部接受采访。通过他的英雄姿态看到了人性的善良，这改变了我的生活。我默默地为他祈祷，然后微笑着回去工作。可知，这个人救了作者的命并让其对生活重拾信心，作者为此感谢他。由此可推断出他们相互感激。故选B。