In what way did the nation's growing transportation system help promote economic growth?

A. It made it easier for Native Americans and freed African Americans to obtain the same goods as white people, boosting demand.

B. Because it added costs for the delivery of goods, it made more profits for the manufacturers.

C. Railroad rebates and pools brought down prices for small farmers, who could afford to modernize their equipment.

D. It opened up national markets for selling and obtaining resources and helped lower costs of production.

I'm really stuck on this one! please help me with this question.

To determine the correct answer, let's break down each option and analyze it:

A. This option suggests that the nation's growing transportation system made it easier for Native Americans and freed African Americans to obtain the same goods as white people, boosting demand. While the transportation system may have improved access to goods, it doesn't directly explain how it helped promote economic growth.

B. This option states that the transportation system added costs for the delivery of goods, resulting in more profits for manufacturers. However, it's important to note that additional costs might not necessarily lead to economic growth. This option doesn't provide a strong connection between the transportation system and economic growth.

C. According to this option, railroad rebates and pools lowered prices for small farmers, allowing them to afford modernizing their equipment. This could potentially contribute to economic growth as modernized equipment can improve productivity and output, leading to increased economic activity.

D. This option suggests that the transportation system opened up national markets for selling and obtaining resources, while also helping lower production costs. This connection between the transportation system and economic growth seems plausible as it expands markets and reduces costs, both of which can contribute to economic growth.

Based on the analysis, option D, which explains how the transportation system opened up national markets and helped lower production costs, seems to be the strongest answer choice.