题目选项分析

In ancient Mesopotamia, prior to 2900 B.C., wheat was cultivated in considerable quantities, but After 2900B.C., production of that grain began to decline as the production of barly increased sharply.Some historians who study ancient Mesopotamia content that the decline in wheat production was due to excessive irrigation, lack of drainage, and the consequent accumulation of salt residues in the soil.

Which one of the following, if true, most help to support the historian's contention concerning the reasons for the decline in wheat production in ancient Mesopotamia?

【选项】Around 2900 B.C., a series of wheat blights occurred, destroying much of the wheat crop year after year.