Question

Which of these helped to further the Westward Expansion in the United States after 1865?

Answer 1

The choices for this question and as follows:

California Gold Rush
Abolition of Slavery
Transcontinental Railroad

I think the correct answer is the last option. It is the Transcontinental Railroad that  helped to further the Westward Expansion in the United States after 1865. Although, it wasn't officially completed, it began to reach further and further west beginning at this time. 

Answer 2

Answer;,
Transcontinental Railroad

Explanation; 
Transcontinental railroad helped further the westward Expansion in the United states after 1865. It was built in the 1860s in North america, linking well developed railway network of the East coast with rapidly growing California. 
The transcontinental railroad really impacted the economy of the US. It allowed for the transportation of goods over long distances