Which of the following activities could be performed by an unlicensed assistant?

An unlicensed assistant is someone who is not legally authorized to perform certain activities or tasks, such as negotiating contracts, collecting deposits, or closing sales. These tasks require specialized knowledge and a license in order to be legally performed. Therefore, options A, C, and D would not be activities that an unlicensed assistant could perform. On the other hand, creating sales brochures does not require specialized knowledge or a license, making it an appropriate task for an unlicensed assistant to handle.