What was lincoln’s strategy for keeping the border states in the union? a)promising abolitionists he would end slavery after the war
b)emphasizing that his only goal was to save the union
c)promising to allow slavery to continue in the border states
d)emphasizing the strength of the industrialized north

b) emphasizing that his only goal was to save the Union.

Explanation:

While Abraham  Lincoln is well known for his debates with Stephen Douglas and played an important role in the discussions about slavery he was not an abolitionist. Lincoln was a nationalist that would do anything for the states stay together and avoid a war in the Union. He said in the First Inaugural Address:

" I declare that “I have no purpose, directly or indirectly, to interfere with the institution of slavery where it now exists. I believe I have no lawful right to do so, and I have no inclination to do so.” Those who nominated and elected me did so with full knowledge that I had made this, and many similar declarations, and had never recanted them.".