[求助]求解呢！！！！！

  In Asian ,where palm trees are non-native ,the trees' folwers have tradtionally been pollinated by hand ,which has kept alm fruit profucyivity unnaturally low.When weevils known to be efficient pollinators of palm flowers were introduced into Asia in 1980.palm fruit productivity increased by up to fifty percent in some area but thrn decreased sharply in 1984.

Which of the following statements, if ture ,would best explain the 1984 decrease in productivity?

A....

B/...

C.Rapid increase in producivity tend to deplete trees of nutrients needed for the development of the fruit -profucing female flowers.

DThe weevil population in Asia remained at approximately the same level between 1980 and 1984

答案选C。我选D。理由是weevil的数量水平没有变，而棕榈树的总量增多了。所以，供不应求，productivity下降。。。

很疑惑？？？

如果按照你的解释，选项D还应该提供棕榈树的总量增多这个条件，但实际上题干和题目中顶多说了fruit有增多