What teaching aid includes any printed matter that instructors distribute before, during, or at the end of a class?

The correct answer is handouts. Handouts are materials that instructors provide to students to reinforce learning, offer additional information, or summarize key concepts discussed during the class. They can be distributed at various points in the instructional process—before the session to prepare students, during the class to accompany lectures or activities, or at the end to serve as a resource for review or additional study.

While brochures, worksheets, and textbooks can serve educational purposes, they have more specific functions that do not encompass the broad range of materials covered under the term "handouts." Brochures are typically promotional materials, worksheets are structured activities for practice and application, and textbooks are comprehensive references or guides for a subject area. Handouts, on the other hand, specifically aim to complement and enhance the learning experience during instruction.