How did the Civil War influence the beginning of American realism? A. Most soldiers came from the middle and lower classes, and Americans wanted to know more about them. B. With the onset of industrial and scientific advances, Americans no longer believed in the supernatural. C. With all of the death and destruction from the war, Americans wanted to escape into an ideal world. D. Despite the industrial and scientific advances, Americans still believed in the supernatural.

Civil war deeply influenced the beginning of American realism as it led the writers to depict the violence, bloodshed, suffered by people in the war and its after-effects including the trauma and despair(the outcome of the war and its conflicts). People were taken aback by the aftermath of the Civil war and therefore, 'they lost faith in supernatural elements' as it had no affiliation to the dark reality of the time.

The writers were now more concerned about highlighting the social and political issues prevailing at the time and therefore, they picked up real-life subjects and presented them in a realistic and true to life manner so that the audience could connect themselves to the characters and the plot. This led to the growth of realism in American literature. Thus, option B would be the correct answer.