Pharos is a pretty good choice
The answer is option A. A territory that was free soil was closed to slaver, while one that had popular sovereignty was allowed to vote on the slavery issue.
The McCulloch v. Maryland is the case that went to the Supreme Court because the state of Maryland wanted to tax the National Bank established by the Congress. The court ruled that under the Article I, Section 8, the "Necessary and Proper" clause that the state could not tax the institution of the the federal government. This is an landmark case and its effect was that this supported the federal government over the state governments.
