Answer:
b. Iowa has a comparative advantage in the production of corn.
Step-by-step explanation:
Iowa's opportunity cost of corn means, for Iowa, the value of the products they need to give up in order to produce corn.
For example, given 2 crops, corn and banana, which have equal price.
Given the fixed amount of resources, to produce a ton of corn, Iowa has to give up 0.5 ton of banana, while Oklahoma has to give up 1 ton of banana. This means Iowa's opportunity cost of corn is lower that that of Oklahoma so Iowa has a comparative advantage in the production of corn.