China has, for centuries, subsisted on a diet consisting

China has, for centuries, subsisted on a diet consisting largely of grains like rice. However, as income levels in China rise, demand for protein based foods has increased. It takes several kilograms of rice grains to produce one kilogram of meat. Therefore, since income levels continue to rise and viable agricultural space for rice production is limited, China will soon have to import more of its food supplies in order to feed the country.

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

(A)

The total acreage devoted to rice production in China will soon decrease.

(B)

Importing either rice or meat will not result in a significantly higher percentage of China's incomes being spent on food than is currently the case.

(C)

The per capita consumption of meat in China is increasing at roughly the same rate across all income levels.

(D)

The per capita income of meat producers in China is rising faster than the per capita income of rice producers.

(E)

People in China who increase their consumption of meat will not radically decrease their consumption of rice.

On this, I reached the correct answer.

How would you go about negating E) in order to test the answer choice and reach the opposite conclusion? Does negation only mean to turn a "will not" into a "will" or do subsequent phrases turn from "decrease" into "increase" etc....?

E.g.

"People in China who increase their consumption of meat will radically increase their consumption of rice."

Thanks a lot.