Passage Summary: Rather than trying to keep people on farms, some economists suggest that cities can solve their problems by trading manufactured goods for the food they need.

Conclusion: Trading urban-produced goods and services for agricultural products is an effective way to handle the challenges of increasing urbanization.

Reasoning: Instead of trying to stop people from moving to cities, planners can have the urban population produce goods to trade for the food that was previously grown in rural areas.

Analysis: To strengthen this argument, we need to bridge the gap between the act of trading and the resolution of 'urbanization problems.' The economists assume that the lack of domestic food production is a primary hurdle or that the trade itself mitigates the strain on urban infrastructure. Look for an answer choice that demonstrates how this economic shift specifically alleviates the negative side effects of a growing city population. We want to see evidence that this trade-based model is actually sustainable or more effective than the traditional method of restricting migration.