Ratifying conventions in three fourth of the states it or three fourths of the state legislatures must approve it, is the correct answer.
Explanation:
Article fifth of the US constitution mentions various methods to amend the constitution
First step in the amendment is the proposal of a bill to amend the constitution. Two thirds of both the houses of the congress can vote for proposing an amendment or a proposal for constitutional amendment convention can be made by two thirds of the state legislatures.
Step two is the ratification of the amendments. It can also happen in two ways. First is by the approval of three fourths of the state legislatures. Second is by the approval of ratifying conventions in three fourths of the states.
Till 2009, 33 amendment has been sent to the states. twenty seven has been ratified
