Answer: Option A
Explanation:
Iowa has an advantage in the production of corn as its citizens chose as their is opportunity to buy corn in Iowa compares to Oklahoma
The prosperity of the 1920s led to new patterns of consumption, or purchasing consumer goods like radios, cars, vacuums, beauty products or clothing. The expansion of credit in the 1920s allowed for the sale of more consumer goods and put automobiles within reach of average Americans.
You can use this as reasoning for it being a positive.
By reading and through context, my guess would be through integration.
