Which of these famous advertising slogans was backed by the most expensive marketing campaign (adjusted for inflation) when it was first introduced?

Advertising slogans can make or break a product's identity in the marketplace. Behind many successful brands are memorable phrases that have become part of our cultural lexicon. These taglines aren't just catchy words—they represent significant marketing investments and strategic positioning. Test your knowledge of which famous advertising slogan required the most expensive marketing campaign to establish in the public consciousness.

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Nike's "Just Do It" (1988)
Apple's "Think Different" (1997)
De Beers' "A Diamond is Forever" (1948)
Coca-Cola's "Open Happiness" (2009)