What was a state that allowed slavery but did not join the confederacy?

your list doesn't mention any of them at all.

and what does "these" mean anyway ?

the compromise of 1850 was a package of five separate bills passed by the united states congress in september 1850, which defused a four-year political confrontation between slave and free states on the status of territories acquired during the mexican–american war

d

explanation:

honestly you should get that checked out because it really isn't normal