A month after this speech, war broke out. Considering the statement above, which f the following best justifies Lincoln's taking military action? a
The Confederates threatened commerce by gaining control of the Mississippi River.

b
The attack on Fort Sumter forced the Union to act in defense of its property.

c
The events at Bull Run encouraged the Union to emancipate enslaved people.

d
The Confederates weakened the Union's authority by imposing blockades on its ports