Final answer:
The 26th Amendment, ratified in 1971, lowered the voting age to 18 years old, ensuring that citizens of that age and older have the right to vote.
Step-by-step explanation:
The 26th Amendment (1971) moved the age to vote to how old? The correct answer is a) 18. The adoption of the 26th Amendment was a significant milestone in the history of the United States. It allowed a broader range of citizens to participate in the electoral process by ensuring that the right of citizens who are eighteen years of age or older, to vote cannot be denied or abridged on account of age. This change was largely fueled by the Vietnam War, where there was a strong sentiment that if individuals were old enough to be drafted and fight for their country, they should also be entrusted with the right to vote. With the ratification of the 26th Amendment, the voting age was standardized to 18 across both federal and state elections, thus uniformly lowering it from the previously common threshold of 21. This amendment was an extension of the ongoing efforts to expand suffrage and make the electoral process more inclusive.