Answer: A. It made travel easier for people migrating west, brought cattle and food products to market, and created jobs for thousands of immigrants working on the railroad.
Explanation: The accomplishment of the First Transcontinental Railroad in 1869 had a huge collision on the West. It inspired further settlement in the West as it made travelling their cheaper and easier. They were forced to move away from the railroad despite it running through Indian Territory. So, your answer's obviously (A.)
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