The fact that the fashion was considered daring in their times suggests that it was something completely new. Of course one might be tempted to choose revealing as the choice for blank one, but "in their times" indicates that something can be daring without being revealing. Neither can proposed be a good choice because there is nothing to suggest these styles were proposed by someone.Thus original is the best choice. And since they have been so widely worn and imitated, it is obvious that the style would no longer be seen as "daring" - so we are looking for a synonym of "daring" and hence outlandish is the correct answer choice.

The meaning and structure of the sentence demand that both the words for the blanks should be synonyms. We cannot find a synonym pair for original and revealing in the answer choices for the second blank.