How does the volume slider affect playback in a DAW?

The volume slider in a Digital Audio Workstation (DAW) primarily functions to adjust the volume of playback. This means that when you manipulate the volume slider, you are controlling how loud or soft the audio from the tracks will be when you play the project. This feature is crucial for balancing different elements within a mix, allowing you to ensure that each track is appropriately heard relative to others.

The ability to adjust volume provides you with the flexibility to create dynamics within your composition, emphasizing certain sounds while allowing others to sit back in the mix. This is an essential task in mixing and mastering music. Therefore, option C accurately describes the role of the volume slider in a DAW.