B. They were going to use the Navy to destroy the forts on the river while the Army attacks over land.
The Union strategy to overtake the city of New Orleans during the Civil War involved a combined naval and land assault. The Navy was tasked with destroying the Confederate forts along the Mississippi River, which would clear the way for Union ships to navigate freely and provide support for the Army. At the same time, the Army was to launch a land assault on the city itself, aiming to capture New Orleans and gain control of the vital port city. This coordinated effort between the Navy and Army ultimately proved successful, leading to the surrender of New Orleans to Union forces in April 1862.