The correct answer is: "The 17th Amendment, allowing for the popular election of U.S. senators, illustrated the growing strength of the progressive movement."
The 17th Amendment to the US Constitution introduced popular elections to appoint US Senators, instead of these being chosen by state legislatures as before.
The Progressive Era was a moment of US history full of intense social activism, in opposition to the issues that had emerged in relation to industralization, such as urbanization, immigration or political corruption.
<u>The 17th Amendment is regarded as a turning point towards transparency in opposition to corruption</u>, as Senators started to be elected through suffrage and not by other public servants who were already in office, and who might be corrupted in the sense that they appoint somebody pursing a particular interest and not because he is the best candidate for the position.
