What was the main reason northern states opposed slavery?

Question

Responses
A the "Declaration" forbade it
B slavery wasn't permitted there
C it went against the Constitution
D it was an unfair business advantage

Answer 1

The main reason northern states opposed slavery was primarily D) it was an unfair business advantage. While some Northern states also held moral objections to slavery and there were legal and constitutional arguments against it, the economic competition and the belief that slavery provided an unfair advantage to Southern states were significant factors in the opposition to the institution in the North.