Your colleague is having an issue with an audio ad campaign and asks you to help troubleshoot it. Within Display & Video 360, which of the following could cause this issue?

In Google Display & Video 360, audio ads must follow specific creative specifications, including the supported file formats for uploaded assets. While formats like MP3 are commonly supported for audio ads, WAV files are not accepted as source files for audio creatives in many DV360 audio ad workflows, which can cause the campaign to fail or prevent the creative from serving correctly. The other options—such as creating an ad in Ad Canvas or missing a companion creative—do not necessarily block an audio campaign from running in this context. Therefore, the issue could be caused because one of the source files is in WAV format, which does not meet the required format specifications.