Although not explicitly stated in the Constitution, what is one additional requirement for the ratification of an amendment to the Constitution that has been upheld by the courts?

a$.$ The amendment must not feature a measure that would harm the life, liberty, or property of others.

b$.$ The amendment must be voted upon each year until it is ratified to the Constitution.

c$.$ The amendment must be ratified within a reasonable amount of time.

d$.$ The amendment must not negatively impact one group for the benefit of another.