Final answer:
The Free Soilers contended that slavery was unsuited to the West (option a) and would undermine the value and dignity of free labor, affecting non-slaveholders and small farmers.
Step-by-step explanation:
The Free Soilers argued that slavery a) was unsuited to the West because it would compete with free labor and thereby reduce its value and dignity. They were not primarily concerned with the morality of slavery or its impact on African Americans, but rather with the negative consequences of slavery on White workers and small farmers. The Free Soilers believed that the expansion of slavery into the West would deprive these groups of economic advancement and maintain a slave-based economy that stifled opportunity and social mobility for poor whites.
Therefore, the answer to the student's question is that the Free Soilers argued that slavery a) was unsuited to the West and b) would cause more costly wage labor to wither away. They did not, however, argue that the profits from slavery would enable small farmers to buy more land or that slavery should be gradually abolished, excluding options c) and d).