Select two correct answers. What are two methods for beginning the constitutional amendment process?

A. An amendment is proposed by a vote of two-thirds of all registered voters in a general federal election.
B. An amendment is proposed by two-thirds of the states through a national constitutional convention.
C. An amendment is proposed by two-thirds of the state legislatures and state convention attendees.
D. An amendment is proposed by a vote of two-thirds of the members of both houses of Congress.