Which amendment process involves a Constitutional Convention called by the states?

The amendment process that involves a Constitutional Convention called by the states specifically refers to the provision allowing two-thirds of state legislatures to propose amendments. According to Article V of the U.S. Constitution, there are two ways to propose amendments: one is through a two-thirds majority vote in both houses of Congress, and the other is through a request for a Constitutional Convention that can be called by two-thirds of the state legislatures. This method emphasizes the role of the states in the amendment process, allowing them to come together to address potential amendments when they see fit, a significant feature as it balances federal and state powers.

The other choices highlight different aspects of the amendment process but do not specifically refer to a Constitutional Convention initiated by states. Ratification by a simple majority occurs after an amendment has been proposed, while the proposal by two-thirds of both houses indicates legislative action rather than state-led efforts. Ratification by three-fourths of the states relates to the requirement needed after an amendment has been proposed, rather than the method of how that proposal can originate primarily through state action.