Answer: Well it would be sentence 13 for simply put its in a form that poses a question.
Explanation: At the Battle of Port Hudson, Louisiana, May 27, 1863, the African-American soldiers bravely advanced over open ground in the face of deadly artillery fire. Although the attack failed, the black soldiers proved their capability to withstand the heat of battle, with General Nathaniel P. Banks recording in his official report: "Whatever doubt may have existed heretofore as to the efficiency of organizations of this character, the history of this day's proves...in this class of troops effective supporters and defenders."Noted for his bravery was Union Captain Andre Cailloux, who fell early in the battle. This was the first battle involving a formal Federal African-American unit.
On June 7, 1863, a garrison consisting mostly of black troops assigned to guard a supply depot during the Vicksburg Campaign found themselves under attack by a larger Confederate force. Recently recruited, minimally trained, and poorly armed, the black soldiers still managed to successfully repulse the attack in the ensuing Battle of Milliken's Bend with the help of federal gunboats from the Tennessee river, despite suffering nearly three times as many casualties as the rebels.