The correct answer is D. They were against the law because it forced them to support slavery
Explanation:
The Fugitive Slave Law was an act of 1850 that established all slaves that had escaped needed to be returned to their masters supporting slavery interests of the Southern states, also, it demanded all states should cooperate to accomplish the act including the Northern states that were against slavery and where the Free Soil Party had begun promoting an opposition to the expansion of slavery. Thus, as the act was signed the Northerners were forced to cooperate and captured all slaves that had escaped to the north and as a consequence support slavery even against their will, due to this the northerners were against the law and opposed to it.
