According to paragraph 2, the estimated population of China in the mid-1700s was?
A. 143 million
B. 150 million
C. 400 million
D. 432 million 为什么答案是B不是A呢。1600年接近150million，随后有下降，1741年大约143 million，1741年就是 mid-1700s ，所以我认为答案是A，请老师指点。
paragraph 2：It is estimated that the Chinese population by 1600 was close to 150 million. The transition between the Ming and Qing dynasties (the seventeenth century) may have seen a decline, but from 1741 to 1851 the annual figures rose steadily and spectacularly, perhaps beginning with 143 million and ending with 432 million. If we accept these totals, we are confronted with a situation in which the Chinese population doubled in the 50 years from 1790 to 1840. If, with greater caution, we assume lower totals in the early eighteenth century and only 400 million in 1850, we still face a startling fact: something like a doubling of the vast Chinese population in the century before Western contact, foreign trade, and industrialization could have had much effect.