The title below that best expresses the ideas of this passage is ______.

A．invented modem mathematical applications
B．were interested in navigation
C．were unaware of the value of their studies
D．were forced to resign themselves to failure

A．They demonstrate how literary changes society.
B．They show that literacy is often imposed on people.
C．They provide conditions in which people can become literate.
D．They enable people to take part in international literacy schemes.