The method of amending the Constitution can be correctly described as "proposal by Congress and ratification by the states."
According to Article V of the U.S. Constitution, amendments can be proposed either by a two-thirds vote in both houses of Congress or by a national convention called by two-thirds of the state legislatures. Then, amendments must be ratified either by three-fourths of the state legislatures or by conventions in three-fourths of the states.
So, the correct options are:
- Proposal by Congress and ratification by the states.
- Proposal by a national convention and ratification by the states.
However, since the question implies choosing one response, "proposal by Congress and ratification by the states" is the most straightforward description.