The tenth amendment is confirming the "founding father" dedication to the principle of

FEDERALISM

Explanation:

   A pertinent analysis is legislative competence in a federal country whose common law system is applied. This is because, as we know, in this system, the law has a primarily jurisprudential face, to the detriment of written laws and regulations.

    In the United States, the dichotomy between state and federal jurisdiction is expressed in the Tenth Amendment to the Constitution: “The powers that the Constitution does not delegate to the United States, and which does not prohibit states from exercising, are reserved to each state, respectively, or the people. ”That is, we clearly have that state power is the rule, with federal competence in the background.

with my knoladg i would say it was c

not sure might be he acquired the entire oregon territory from great britain