The north’s anaconda plan was based on

The Anaconda plan was based on the blockade of South trade, since these depended on cotton trade primarily.

Explanation:

The Anaconda Plan was the name given to a military project of the United States Civil War, created by Union General Winfield Scott, and entered into force in 1862. The Plan instituted a siege of the Confederation by the Union, through a naval blockade, control of the Mississippi River and the Tennessee River, completely enclosing and dividing the Confederation. The naval blockade on this one - whose objective was to suppress the export of cotton, tobacco and food to European countries, and the importation of armament - implied a constant surveillance of 4,800 kilometers of southern coast, a task considered impossible from the beginning. Scott popularized the term "Anaconda Plan", because similar to the South American anaconda, which kills its victims by curling around them until suffocating them and breaking their bones, the North intended to destroy and "asphyxiate" the economy of the South "imprisoning" their territories through a blockade.

i think it is the third one.