Which of the following is considered a non-projected teaching aid?

A non-projected teaching aid is typically one that does not require a visual projection system to convey information to learners. An audio recording fits this definition perfectly, as it relies solely on sound to communicate content, allowing the audience to receive the information purely through auditory means. This makes audio recordings highly effective in scenarios where visual aids may not be available or appropriate, enabling instructors to focus on dialogue, sound cues, and auditory learning styles.

In contrast, other options like PowerPoint presentations, video recordings, and slide projectors all utilize visual elements that need screens or projectors to display information. These types of teaching aids are designed to enhance learning through visual stimuli, making them classified as projected aids. Therefore, the focus on auditory engagement in teaching is what distinguishes audio recordings as a non-projected teaching aid.