Which of the following amendments is associated with the voting rights of younger citizens?

The 26th Amendment is associated with the voting rights of younger citizens as it specifically lowered the voting age from 21 to 18 years. Ratified in 1971, this amendment was significant in extending the right to vote to a younger population, particularly in response to arguments that individuals who were old enough to be drafted for military service should also have the right to participate in elections. This change reflected a growing acknowledgment of the importance of youth voices in shaping democratic governance.

In contrast, the 19th Amendment granted women the right to vote but did not address age; the 23rd Amendment provided voting rights to residents of Washington D.C. in presidential elections, and the 21st Amendment repealed Prohibition, which again does not pertain to voting age. Thus, the 26th Amendment is the one that directly pertains to the voting rights of younger citizens.