The correct answer is option "B". The power to establish post offices and post roads is held at the Federal level, as it is stated in the Article I, Section 8, Clause 7 of the US Constitution, and it is also known as the Postal Clause or the Postal Power. By means of this article, the Congress has the power to establish post offices and designate post roads or mail routes to carry, deliver, and regulate the mails of the United States as a whole.
