Answer:
B) The Union realized that the war would not end quickly and easily.
Explanation:
The First Battle of Bull Run, also known as the First Battle of Manassas, took place on July 21, 1861 and was the first major ground combat of the American Civil War. Unspoken federal troops, under the command of Brigadier General Irvin McDowell, advanced against the Confederate Army, commanded by Brigadier Generals Joseph E. Johnston and PGT Beauregard, in Manassas, Virginia, and despite their preliminary success they were forced to retreat finally to Washington DC
