A constitution that requires a plebiscite or a referendum to be amended is
rigid
unwritten
flexible
written
Correct answer is A
Plebiscite; the direct vote of all the members of an electorate on an important public question such as a change in the constitution.
A referendum; is a direct and universal vote in which an entire electorate is invited to vote on a particular proposal and can have nationwide or local forms.
A rigid Constitution; is a constitution that is difficult or slow to change usually because of a prescribed process of amendment that is detailed and lengthy in execution.