The land was free and perfect for farming, if settlers survived the journey to Oregon the land was all theirs. But not only did the US like it, Britain and Russia also liked it. So the US told people to move there ASAP so it would officially be claimed by America.
A and C can work and D is partially true I would go with a or d tho
The answer to this is federalism
Bloodies battle is: battle of Sharpsburgh
