In the author's opinions, which one would be the most insolvable problem caused by population growth

A．Our own compulsory school attendance first became law in German in 1642.
B．"equal start" is the ideal modern education is trying to regain.
C．The real equality of opportunity in education is only to be found in a modem society.
D．An illiterate man in modem society is deprived of one of the greatest opportunities.

A．makes sure there are no illiterates
B．comes into being relatively recently
C．is enjoyed only by the noble people
D．is free to everyone who is a citizen