The United States had strong influence of Christianity since the Pilgrims and many others who brought and taught about God and faith, also about the importance of missionary outreach. Nevertheless, unfortunately, the goal and interest for expanding, in this period, <em>was not</em> the desire to extend Christianity and a life of faith.
Letter A is correct. Many are the reasons that led to the United States expansion, but the desire to extend Christianity was not one of them. The U.S expanded westward across North America, initially as part of 'Manifest Destiny', but also as an outlet for their growing population. They also wanted an overseas empire like the other major western powers at the time (such as Britain and France). And, that included new markets and sources of revenue along with a more proeminent position on the world stage.
Some of the peoples it conquered didn't want to be ruled by the Incas and were rebellious, mainly, and it was so big that it couldn't keep the conquered in line very well.
