The Emancipation Proclamation affected the Union’s Civil War efforts by
A. allowing the Union to turn its attention away from slavery.
B. increasing the number of available troops for the Union.
C. forcing Southern slaveholders to free enslaved people.
D. forcing Northern African Americans to join the Union army.

b. increasing the number of available troops for the union

Explanation:

i took the test : )

b.

Explanation:

It said that african americans could now join the military in the union

the correct answer is “opportunity cost”. opportunity cost is what a company misses out because it decided in one option over another one. in this case, the company decided to invest in building a factory so it gave up another possible benefit or profit in order to achieve success with the factory.  

trade-off is not the correct answer since it is a situation in which you accept losing something in return for benefits in other areas.

and finally, consequence is a general term used to accept what it comes when you make a decision. it can be a positive or negative consequence depending if the decision you took was the correct one.  

the answer is aggresion hope this and mark me as brainiest and add me as friend