Tactical Supply What Was The Tactical Focus Of The Union Navy During The Civil War?

What was the tactical focus of the union navy during the civil war? - tactical supply

A: The control of the Mississippi River, the federal government divided and easier than driving to victory.
B: control of certain key ports in the south, which would restrict the ability of the federal government for trading with foreign countries.
C: the elimination of smuggling vessels, which were the main source of supply for the south.
D: starve a whole block south of the Federal submit.

I think B, but I want to assure you that this is a test at home.