Which is a problem caused by having an export economy? A. They rely too much on import tariffs. B. African businesses have to compete with each other. C. Export economies lead to quick industrialization. D. It causes a reliance on world market prices.

To determine which option represents a problem caused by having an export economy, let's analyze each choice: A. **They rely too much on import tariffs.** This statement does not directly relate to the problems of an export economy. Export economies focus on selling goods abroad rather than relying on tariffs. B. **African businesses have to compete with each other.** While competition can be a challenge, this is not a specific problem caused by an export economy. It is more about the internal market dynamics. C. **Export economies lead to quick industrialization.** This is generally seen as a benefit rather than a problem. Quick industrialization can be a positive outcome of an export economy. D. **It causes a reliance on world market prices.** This is a significant problem associated with export economies. When a country relies heavily on exports, it becomes vulnerable to fluctuations in global market prices, which can affect its economy negatively. Based on this analysis, the correct answer is: **D. It causes a reliance on world market prices.**