The correct answer is C. The effect of the Battle of Chancellorsville on the Confederate Army was that they gained the confidence to attempt a second invasion of the North.
The Battle of Chancellorsville was fought near Spotsylvania Courthouse, Virginia, between April 30 and May 6, 1863, during the Civil War. The battle faced the Army of the Potomac against the Confederate Army of Northern Virginia led by General Robert E. Lee, who had half the troops that the Union had. It is known as Lee's "perfect battle" because of his risky but successful decision to split his army in the presence of a far superior enemy force. This victory gave the Confederates the confidence to advance in the territory of the Union, attempting an invasion.