A、I love you. B、I’ll be there. C、Maybe you’re right. D、There’s no charge. B原文提到“最有用的一句话就是‘I’ll be there’(我就来，我会在那里)”。故选B。

The most important message that humans deliver to one another often comes in just three words. Think of "I love you" or "There’s no charge". One of the phrases that I found most useful is this, "I’ll he there". I’ll he there", and if you ever have to call a plumber over the weekend yon know how good these words can feel. If you heard them after having car trouble on the road and used a last coin to call a friend, you know the feeling too. "Grandma, I’m graduating in June." "I’ll be there." "Fanny, I’m stuck in the office and I can’t get to the airport to meet my sister." "I’ll be there." "Mum, the baby cries all night, and if I don’t get some sleep I will perish." "I’ll be there."
    One person who really knows how to be there is Elizabeth, the queen mother of England. During the air attack on London in 1940, she was asked whether the little princesses Elizabeth and Margaret Rose would leave London for their safety. The Queen replied "The children would not leave unless I do. I shall not leave unless their father does." The Queen would not leave the country at any circumstances however. "I’ll be there."
    Another three-word phrase is one of the hardest to learn to say. It’s "Maybe you’re right". If more people would say "Maybe you’re right", the marriage mediators would go out of business, I know from experience it can have a charming effect in an argument.
23. What are the three words that the speaker found most useful?
24. What did Queen Elizabeth decide to do during the air attack on London?
25. What would happen if more people say "Maybe you’re right"?