Answer: the correct answer is a. His reinforcements saved Confederate troops from defeat.
Step-by-step explanation:
He was appointed a brigadier general in the Confederate Army and took command of forces garrisoned at Harpers Ferry. Johnston played a major role in the first major victory of the war in July 1861, when he reinforced General P.G.T. Beauregard and oversaw a routing of Union troops at the First Battle of Bull Run (Manassas).