阅读理解:阅读下列短文，然后从每题所给的四个选项(A、B、 C、和D)中，选出最佳选项。
An important question about eating out is who pays for the meal. If a friend of yours asks you to have lunch with him, you may say something like this,“I'm afraid it'll have to be someplace cheap, because I have little money.” The other person may say, “OK, I'll meet you at McDonald's.”
This means that the two agree to go Dutch, that is, each person pays for himself. He may also say, “Oh，no，I want to take you to lunch at Smith's,”or“I want you to try the Chinese dumplings there. They are great.”This means the person wants to pay for both of you. If you feel friendly towards the person, you can go with him and you needn't pay for the meal. You may just say, “Thank you. That would he very nice.”
American custom(习惯) about who pays for dates (约会) are much the same as in other parts of the world. In the old days, American women wanted men to pay for all the meals. But, today, a university girl or a woman in business world will usually pay their way during the day. If a man asks her for a dance outside the working hours, it means “Come, as my guest.”So as you can see, it is a polite thing to make the question clear at the very beginning.
，则P与M关系为 （ ）
