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.
During the Industrial Revolution, environmental pollution increased with the use of new sources of fuel, the development of large factories, and the rise of unsanitary urban centers.
This meant that they could not govern themselves and make their own laws. They had to pay high taxes to the king. They felt that they were paying taxes to a government where they had no representation. They were also angry because the colonists were forced to let British soldiers sleep and eat in their homes.