Answer: The correct answer is B.
Explanation: The Articles of Confederation required a unanimous vote of all 13 states to amend the document, making it very inflexible. The U.S. Constitution, on the other hand, allows for amendments to be proposed by a two-thirds vote of Congress or by a convention called for by two-thirds of the state legislatures. These amendments must then be ratified by three-fourths of the states, but this process allows for changes to be made to the Constitution, making it more flexible than the Articles of Confederation.