Final answer:
The Free Soil Party of 1848 primarily opposed the expansion of slavery into territories because of the economic impact on free white laborers, rather than seeing slavery as a moral evil. The correct answer is option B.
Step-by-step explanation:
The Free Soil Party of 1848 primarily opposed the expansion of slavery into the territories for the reason that it would harm the prospects of free white laborers. This political group did not primarily see slavery as a moral evil to be eradicated everywhere; rather, it focused on how slavery in the territories would undermine the dignity and opportunities of white workers.
By advocating for "Free Soil, Free Speech, Free Labor, and Free Men," the party posited a viewpoint that slave labor would compete with free labor in the western territories, preventing white laborers from rising and maintaining a wage-earning independence. This stance suggests that the most accurate answer to the student's question is Option B, as it reflects the Free Soil Party's goal to protect economic opportunities for white workers in new territories from the competition of slave labor.