About question 9,10 on test D

qiushuan

Questions 9-10 are based on the following.
In the industrialized nations, the last century has witnessed a shortening of the average workday from twelve hours or longer to less than eight hours. Mindful of this enormous increase in leisure time over the past century, many people assume that the same trend has obtained throughout history, and that, therefore, prehistoric humans must have labored incessantly for their very survival.
We cannot, of course, directly test this assumption. However, a study of primitive peoples of today suggests a different conclusion. The Mbuti of central Africa, for instance, spend only a few hours each day in hunting, gathering, and tending to other economic necessities. The rest of their time is spent as they choose. The implication is that the short workday is not peculiar to industrialized societies. Rather, both the extended workday of 1880 and the shorter workday of today are products of different stages of the continuing process of industrialization.
9. Which of the following inferences about industrialization is best supported by the passage above?
(A) People in advanced industrialized societies have more leisure time than those in nonindustrialized societies.
(B) An average workday of twelve hours or more is peculiar to economies in the early stages of industrialization.
(C) Industrialization involves a trade-off between tedious, monotonous jobs and the benefits of increased leisure.
(D) It is likely that the extended workday of an industrializing country will eventually be shortened.
(E) As industrialization progresses, people tend to look for self-fulfillment in leisure rather than work.
the answer is D

10. Which of the following, if true, would most greatly strengthen the argument made in the passage above?
(A) In recent decades, the economy of the Mbuti has been markedly affected by the encroachment of modern civilization.
(B) The life-style of the Mbuti is similar to that of prehistoric humans.
(C) The Mbuti have no words in their language to express the distinction between work activities and leisure activities.
(D) The workday of a European peasant in medieval times averaged between eleven and fifteen hours.
(E) The members of the Shaklik tribe in central Asia have an average workday of ten to twelve hours.
the answer is B

i had look up the old discussion on these 2 questions. but i still can't got a clear explanation for it.
Would anyone help with this? I will appreciate that!