Which landmark U.S. legislation first required political advertisements to clearly disclose their funding sources with the now-famous 'I approve this message' tagline?

In the world of politics, campaign financing and advertising are heavily regulated. Legislation has evolved over decades to increase transparency and accountability in how political campaigns are funded and advertised. This trivia question tests your knowledge about a landmark piece of legislation that significantly changed how political campaigns operate and disclose their advertising efforts. How well do you understand the laws that govern political advertising campaigns?

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Bipartisan Campaign Reform Act of 2002 (McCain-Feingold Act)
Federal Election Campaign Act of 1971
Citizens United v. FEC Supreme Court Decision (2010)
DISCLOSE Act of 2012