Who elects U.S. senators?

What does this answer mean?

Citizens from their state elect U.S. senators. In a Senate election, voters across the whole state choose the winner.

It wasn't always this way. The Constitution originally said state legislatures would choose senators. The 17th Amendment, ratified in 1913, changed that so senators are elected by the people of each state. The amendment also lets a state's legislature allow the governor to appoint a temporary senator when a seat becomes empty, until voters fill it in an election.

Senators serve six-year terms, and about one-third of the Senate is up for election every two years. Only U.S. citizens can vote in federal elections, which is the answer to another question on the test.

Compare this with the House: members of the House are elected by citizens from their congressional district, not the whole state.

At the interview, say "citizens from their state."