According to article i, section 3 of the constitution, each united state's senator must be
an adult who is at least twenty-five years old.
a lifetime resident of washington, dc.
a registered voter in one’s state.
a us citizen for at least nine years.

a US citizen for at least nine years.

Article I, Section 3 of the United States Constitution defines the way in which senators are to be elected, and the requirements that are necessary in order to perform that role. It states that a senator must be thirty years of age, and he needs to have been a citizen of the United States for nine years. Moreover, when elected, he should be an inhabitant of the State for which he is chosen.

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