What type of file does M4A refer to?

M4A refers to an audio-only file format. This format is primarily used for audio storage and is derived from the MPEG-4 format. It typically supports lossy audio compression using the AAC (Advanced Audio Codec) or Apple Lossless format, allowing for high-quality sound in a smaller file size. M4A files are commonly used for music files, podcasts, and audiobooks, and they are widely supported by various media players and devices.

In contrast, the other options involve different types of media formats. Video formats, image formats, and text document formats serve specific purposes that are distinct from audio file formats. Therefore, they do not accurately represent what M4A denotes. Understanding the specific characteristics of file types is crucial in fields like IT, as it helps in choosing the right format for the necessary application.