How old do citizens have to be to vote for President?

The requirement for citizens to be eighteen years old to vote for President is established by the 26th Amendment to the U.S. Constitution, ratified in 1971. This amendment lowered the voting age from twenty-one to eighteen, ensuring that young adults who are legally recognized as adults are able to participate in elections. This change reflected a growing recognition of the rights of younger citizens, especially in light of social movements and the argument that those old enough to be drafted for military service should also have the right to vote.

The other age options do not align with the current legal voting age. Sixteen and seventeen-year-olds do not have the legal capacity to vote in presidential elections, as they have not reached the age of majority designated by federal law. Similarly, twenty-one was the voting age prior to the ratification of the 26th Amendment, so it is no longer applicable. Thus, the correct answer highlights the current legal framework governing the voting age in the United States.