The most accurate response regarding the evolution of the process to enfranchise more people throughout U.S. history is:
The addition of new amendments to the Constitution has taken place slowly over many decades.
This reflects the gradual progression of voting rights, including significant amendments such as the 15th (prohibiting voting discrimination based on race), the 19th (granting women's suffrage), and the 26th (lowering the voting age to 18), which were all enacted over a span of many years.