Why is Vera allowed to borrow one book only?

A. Choose A, B, C, or D for the correct answer.

The folbwing dialog is for questions 1 to 3.

Vera: Excuse me. l' d like to borrow these books, Sir.

Mr. Edo: O.K. How many books do you want to borrow?

Vera: Three.

Mr. Edo: Sorry. According to the rule, you mustn't borrow more than two books.

Vera: I see. Then, I will just borrow these two books.

Mr. Edo: Can you give me your member card?

Vera: Sure. Here it is.

Mr. Edo: Oops ... you are still borrowing one book. Will you return it?

Vera: No. I am still using it to do my work.

Mr. Edo: If that's so, you are only allowed to borrow one more book.

Vera: Yes, Sir. I'll take this one. 

Mr. Edo: You have to return this book in one week. If you want to borrow it for another week, you have to bring the book here and show your member card.

Vera: O.K., Sir

Why is Vera allowed to borrow one book only?