your answer is gonna be A
Chines, Irish immigrants, and African Americans
Answer:
At the start of the war, the Union didn't have a very organized spy network. Although they had a lot of spies, they were usually sent out by individual generals or leaders in the government. The information wasn't communicated very well or passed on to the people who really needed it. The Union had a distinct advantage in the war as they gained a significant amount of military intelligence from slaves and former slaves.
As the war continued, the lead generals of the North had a spymaster who would organize and gather the information from the spy network.