The correct answer is: General William Tecumseh Sherman's March to the Sea destroyed Southern transportation lines.
The Sherman's March to the Sea is the name given to the military campaign led by US General William Tecumseh Sherman with his Union Army troops in the American Civil War. This campaign began after the triumphs of Gettysburg and Vicksburg. By mid-1863 the Union troops had the opportunity to launch a major offensive from the state of Tennessee to Georgia, in the very center of the territory of the Confederate States. After Sherman's troops took Atlanta on September 2, 1864, they set out to advance through Confederate territory to reach the Atlantic Ocean, defeating all the Confederate troops that could find and destroying industries, railroads, mills, canals, warehouses, farms, workshops, and practically every element that served to sustain the economy of the secessionist states.
This policy of Sherman and his troops caused very serious damage to the industry and infrastructure of the Confederation, causing severe devastation as the northern troops moved into unknown territory, without supply lines, and with Sherman's order to subsist on the base of the crops and livestock that they could steal or loot from the farms that they found in their way, destroying the livestock and surplus crops.