Which is not one of the "suffrage amendments"?

15th amendment - right of citizens of the U.S. to not be denied the right to vote (suffrage)
19th amendment - granted American women the right to vote (suffrage)
25th amendment - if the president dies then the vice president becomes new president 
26th amendment - if you're 18 and over you can vote (suffrage)

So the answer would be C.25