Final answer:
The correct answer is option b.) 13.
Step-by-step explanation:
The ratification of the U.S. Constitution required approval by at least nine states. This was outlined in Article VII, which stated that 'The Ratification of the Conventions of nine States, shall be sufficient for the Establishment of this Constitution between the States so ratifying the Same.' Ratification occurred in individual state conventions, rather than at the Constitutional Convention of 1787 or through a popular referendum. Delaware was the first state to ratify the Constitution on December 7, 1787.
Eventually, New Hampshire became the ninth state to ratify in 1788, which was the minimum requirement for the Constitution to become law, according to Article 6: Ratification. Rhode Island was the last of the thirteen states to ratify, officially doing so on May 29, 1790, making unanimous ratification by all 13 states.
Adding to this context, the promise of a Bill of Rights was integral to secure ratification of the Constitution. After the Constitution's drafting, James Madison worked to formulate the first ten amendments, based on suggestions from state conventions, which became the Bill of Rights in 1791 after being ratified by three-quarters of the state legislatures.