"much of the national harmony had rested upon the existence of a kind of balance between the northern and southern parts of the united states. the decision to fight the [mexican-american war] had disturbed this balance, and the acquisition of a new empire which each section desired to dominate endangered the balance further. thus, the events which marked the culmination of six decades of exhilarating national growth at the same time marked the beginning of sectional strife which for a quarter century would subject american nationalism to its severest testing." — david m. potter, historian, the impending crisis: america before the civil war, 1848–1861, published in 1976 the following four questions refer to the excerpt above 1. which of the following most directly maintain the "balance between the northern and southern parts of the united states" before the mexican-american war referenced in the excerpt? a. the federal government’s policies on a national bank and tariffs b. the emergence of reform movements during the second great awakening c. the outlawing of the international slave trade d. the passage of the missouri compromise