___________ hide the offstage areas from the audience

The correct answer is legs. In theatre design, legs are vertical curtains or fabric pieces that are typically hung on either side of the stage. Their primary purpose is to mask the offstage areas from the audience's view, effectively creating a defined performance space. By doing so, they help maintain the illusion of the world being portrayed on stage and prevent the audience from seeing backstage activities or the equipment used in the production.

Teasers, while also used to hide elements of the stage, are horizontal drapes that cover the top of the stage and are more focused on concealing lighting rigs and other overhead components rather than side areas. Grand drapes serve as a grand curtain at the front of the stage, which can also conceal backstage areas but are not responsible for side masking. Travelers, referring to curtains that open and close by sliding horizontally, can also serve a masking purpose but are typically more associated with acting as entrances or exits rather than solely hiding offstage areas. The legs are specifically designed for this purpose, making them the most appropriate choice.