A、The account number is 51406881. B、The account number is 21406881. C、The woman faked lots of invoices. D、There is no informatio

W: Well, Mr. Smith, I’ve looked into your invoice and found out why it hasn’t been paid.
    M: Why?
    W: We asked our bank to transfer the money but they couldn’t. (6) They said that your bank details were wrong. So they couldn’t transfer the money then.
    M: What do you mean my bank details were wrong? They are printed on our invoice. I think that you receive the same invoice as all our other customers.
    W: I’m sorry. What did you say?
    M: I said our bank details were printed on the invoice.
    W: Well, I have the invoice here. Can we just check? (5) The account number is 21406881. Is that right?
    M: Yes, that’s right. And what about the name of the bank?
    W: At the Bank of Scotland at 46 Portland Street in...
    M: Hold on, did you say Bank of Scotland?
    W: Yes. What’s the matter?
    M: (6) It is the Royal Bank of Scotland, not the Bank of Scotland.
    W: You mean there are two different banks?
    M: Exactly.
    W: OK, Mr. Smith. (7) I’ll ask our bank to transfer the amount to the Royal Bank of Scotland as soon as it opens. I’m sorry about the mistake.
    M: Well, I’m glad we’ve sorted it out.
    Questions 5 to 8 are based on the conversation you have just heard.
    5. What can we know about the invoice from the speakers?
    6. Why can’t the woman transfer the money to the man?  
    7. What does the woman promise to do?
    8. What is the probable relationship between the two speakers?