The growth of rail and telegraph during American expansionism was significant for spreading American influence, enhancing internal development, and facilitating trade; thus, the correct answer is 'ALL OF THE ABOVE'.
The growth of rail and telegraph systems during the expansionist period in American history was significant for several reasons. Expansionists praised these technological advancements because they helped to spread American influence across the continent, notably by making communication and transportation more accessible and faster. Furthermore, the development of rail and telegraph allowed for enhanced internal development of cities and towns by connecting distant communities which were previously isolated. An additional benefit was the ability to facilitate trade by moving goods more efficiently across vast distances, thus bolstering economic growth and market expansion.
So, expansionists saw the rail and telegraph as vital tools for achieving multiple objectives that were crucial for America's growth. Therefore, the correct answer to the given question would be D. ALL OF THE ABOVE, as these innovations were instrumental in spreading influence, enhancing development, and facilitating trade.