The word "cumulative" in Paragraph 1 most probably means ______.

A．Slaves in Greece in the sixth century B. C. were not politically significant.
B．The "burghers" of the later Middle Ages constituted an entirely new social class.
C．To some extent, social mobility can be attributed to the growth of trade.
D．The new class made up of traders and executive officials of the later Middle Ages made the development of a money economy possible.

A．the cultural pattern is the single factor that affects a child's upbringing in the home
B．by no means does the technological development of a community contribute to the development of children's character
C．there are advisable rules for parents to go by in bringing up their children
D．upbringing and education are mutually complementary