China Southern Airlines currently offers online booking services for travelers, however, telephone bookings will not be reduced in the near future. Which of the following items cannot explain the above phenomenon:. ['The online booking system is in a trial period, and many travelers prefer to book by phone for insurance purposes.', 'At the peak tourist season, the number of bookings will increase significantly.', 'The overwhelming majority of travelers who travel by telephone have not yet qualified to use the Internet.', 'The cost of online booking services is much lower than telephone booking, and it also has other service functions not available in telephone booking.']