Answer:
C.) Secession
Explanation:
It states "debated the question of _____, or withdrawing from the Union."
Commonly in writing this is a writing form where a word exists and a comma is added to describe the word in an easier to understand way. (Sorry if that didn't make sense.)
In this case, Secession is to withdraw from the Union.
Also, I took this test and got an A.
If you got another answer feel free to tell me!
Hope this helped despite the fact that I'm a little late!