Of the following options that were presented together with the problem, the most probably answer would be D. Superior military leader.
During the civil war, there were advantages and disadvantages for both the North and the South. The south had a strong disadvantage with mobility and supplies since there were less rail roads for their soldiers to utilize and less factories were present to re-supply. This makes options A. and C. a mistake. As for B. a larger population, that isn't quite the picture the South had during the civil war since most of their man were enslaved and to begin with, they were outnumbered in population by the North where the South only had a total of 9 million and the North had a total of a staggering 22 million. As for the correct answer, it connotes not just to a single individuals but to a number of officers of the United States. They weren't just officers, but were given the title of being the best officers in their respective fields.
