Which "scandalous" dance step gained popularity through Broadway revues and silent films?

The tango is the correct choice because it became widely popular in the early 20th century and was often associated with scandalous and risqué connotations. Originating from Argentina, the tango's passionate and intimate dance style captivated audiences and was showcased in various Broadway revues and silent films of the era. Its distinct movements and close embrace were seen as provocative compared to the more restrained styles of dance popular before its rise. The tango not only influenced popular culture but also helped to reflect and challenge social norms of the time, making it a significant dance style in the context of American entertainment history.

Other dance styles, such as the Charleston, polka, and jitterbug, had their own unique contexts and popularity, but they did not carry the same level of "scandalous" reputation associated with the tango during the period in question.