C: "...the sudden end to the slave economy would have had a profound and killing economic impact in the South where reliance on slave labor was the foundation of their economy" was NOT one of the reasons Lincoln gave for his hatred of the spread of slavery.
Lincoln was a vocal opponent of the spread of slavery and gave several reasons for his opposition. In his speeches and writings, he argued that slavery was a "monstrous injustice" that violated the principles of freedom and equality enshrined in the Declaration of Independence. He also believed that the spread of slavery enabled critics of the United States to attack the country's commitment to democratic values and principles. Additionally, he argued that the expansion of slavery threatened the future of free labor and the opportunities for economic advancement it provided. Finally, he believed that slavery was fundamentally incompatible with the principles of civil liberty and represented a threat to the survival of the Union.
Therefore, option C was not one of the reasons Lincoln gave for his hatred of the spread of slavery.