Advertisement is mainly paid for by______.

A．it is important to be successful in teaching the young
B．enough salaries are necessary in making quality people become teachers
C．greater progress has to be made in teaching
D．teaching is a product of the society's division of labor

A．family members had been responsible for the 'education of the young
B．specialists had been in charge of teaching young people
C．young people had had to be self-educated
D．the society had played an important role in educating young people