According to the passage, which book is the only book you'll ever need

A．It can contain a library of information or every title on today's best-seller list.
B．Although we know the basic technology, we can't see it for sale now.
C．The laptop needs a lot of power to keep LCD screens work, and those screens have shortcoming.
D．You can change the title and the content in the electronic book as you lik

A．we haven't mastered the manufacturing technology yet
B．the electronic ink which must be conductive couldn't be produced in large scale
C．the electronic book will be too expensive to buy
D．you can't take an electronic book with you anywhere