The correct answer is B) The power to ratify changes to the Constitution.
The federal government is given the ability to tax citizens multiple times. This includes Article 1 Section 8 of the US Constitution and the 16th amendment (which establishes the federal income tax).
The power to regulate interstate commerce is also in Article 1 Section 8 of the US Constitution. This was further reinforced by the Supreme Court case Gibbons vs. Ogden.
The US Constitution also explicitly gives the right to sign treaties to the federal government.
This is why B can be the only correct answer.
The north's economy was based predominantly on manufacturing,shipping, and other factory businesses.
In the south, however, most of the economy was agricultural, requiring many farmworkers.
