An example of the avant-garde approach would typically involve a style that challenges conventional norms and encourages the audience to think differently. In this context, none of the provided options strongly exemplify the avant-garde approach, as they all rely on more traditional forms of advertising.
However, if we had to choose one that might slightly lean towards an avant-garde technique by suggesting uniqueness or originality, it would be:
"an ad for a new type of athletic shoe that uses the slogan Be the First to Wear the Best."
This option implies a sense of novelty and encourages consumers to be trendsetters, which aligns more with avant-garde principles compared to the other options.