There are two maps on the wall: one is a map of China, and（）is a map of the world.（）

A. you can read an e-book on a laptop when you travel
B. you can order an e-book using the E-book Reader
C. the e-books ordered have to be shipped to you
D. it takes a lot of trouble reading an e-book

A. if they reserve tickets at a hotel
B. if they buy tickets at the airport
C. before receiving the Permanent Card
D. after receiving the Permanent Card