Which of the following can be the title of this passage（）

A．Because people hate the businessmen using mobiles in public places.
B．Because the use of mobile phones can be physically harmful.
C．Because there is strong evidence for the problems of mobiles.
D．Because people feel their privacy unprotected in a caf6 or restaurant.

A．mobile phones are very fashionable with teenagers
B．they can call home if they are in trouble and need help
C．they can use mobiles to play simple computer games
D．mobile phones enable teenagers to give up smoking