Which of the following is the most likely reason that Lincoln did not emancipate all slaves?

In January 1863 during the Civil War, President Abraham Lincoln's Emancipation Proclamation freed more than three million slaves who lived in the Confederate states. Lincoln stated:

"And by virtue of the power and for the purpose aforesaid, I do order and declare that all person held as slaves within said designated states and parts of states are, and henceforward shall be, free; and that the Executive Government of the United States, including the military and naval authorities thereof, will recognize and maintain the freedom of said persons.

And I hereby enjoin upon the people so declared to be free and abstain from all violence, unless in necessary self-defense; and I recommend to them that, in all cases when allowed, they labor faithfully for reasonable wages.

And I further declare and make known that such persons, of suitable condition, will be received into the armed service of the United States to garrison forts, positions, stations, and other places, and to man vessels of all sorts in said service. "

Source: HistoryCentral. com.

Lincoln did not want to appease radical abolitionist groups.

He believed slavery was an economic necessity.

He did not want to upset the slaveholding states that were loyal to the Union—Delaware, Maryland, Kentucky, and Missouri.

Lincoln did not believe that the complete abolition of slavery was possible.

He wanted to uphold the Supreme Court decision in the Dred Scott case, which said that Congress could not regulate slavery in new territories.

Lincoln was reluctant to issue an order that abolished slavery throughout the nation out of loyalty to the four border states that stayed with the Union

Was asked in this test : Social Studies Pre 1