Gortland has long been narrowly self-sufficient in both grain and meat.

However, as per capita income in Gortland has risen toward the world

average, per capita consumption of meat has also risen toward the world

average, and it takes several pounds of grain to produce one pound of meat.

 Therefore, since per capita income continues to rise, whereas domestic

grain production will not increase, Gortland will soon have to import

either grain or meat or both.

Which of the following is an assumption on which the argument depends?

(A) The total acreage devoted to grain production in Gortland will soon

decrease.

(B) Importing either grain or meat will not result in a significantly

higher percentage of Gortlanders' incomes being spent on food than is

currently the case.

(C) The per capita consumption of meat in Gortland is increasing at roughly

the same rate across all income levels.

(D) The per capita income of meat producers in Gortland is rising faster

than the per capita income of grain producers.

(E) People in Gortland who increase their consumption of meat will not

radically decrease their consumption of grain.

答案是E，请nn帮忙解释一下，同时理一下这道题的思路，感谢！

"whereas domestic grain production will not increase, Gortland will soon have to import either grain or meat or both."

there is another possible explain, that is, if people in gortland consume grain decrease,the decrease amount of grain maybe balance the increase amount that meat require, therefore, gorland may not nessarily import grain from outside. it will weaken the argument.

plus E, the argument will be strenthened.

hope this can address your confuse.

good luck