The correct answer is the following.
As the Civil War progressively badly for the North the three things that plagued Lincoln were the following.
The first thing was that the Union moral was eroding. Every day that passed affected the moral of the Union army. The second was the necessity to find a strong suitable military leader to command the troops. The third was to find a feasible and prompt solution to defeat General Lee’s Confederate troops.
Abraham Lincoln had to make decisions and move swiftly to create a turn of events that favored the Union. He found in General Ulysses Grant the right man to be at the front of the Union war efforts and then things began to change for the Union.