Answer:
C.) Lincoln's efforts to abolish slavery
Step-by-step explanation:
Lincoln had two great successes in his two terms as president, the first was to abolish the slavery of people of color, based on the fact that all men are equal and born free, this was a great struggle, which generated many consequences, among which This is the civil war that the southern states undertook, but even so, this was not an impediment to leaving their mark on history for abolishing slavery.