The correct answer is A.
After the Constitution was signed in 1787, many states feared that the newly created federal nation would take over some of its power. This is why the tenth amendment was developed, stating that "the powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the States respectively, or to the people.”
In opposition to the Articles of the Confederation, were states could only hold the powers explicitly included in their list (police powers, health, education, and welfare), now also the implied powers described above are granted to the states.