Audio description (AD) is an audio track that narrates the relevant visual information in media.
AD assumes that the viewer cannot see, and therefore depicts the key visual elements that are necessary to understand the content for blind and low vision viewers. By adding AD to your adverts, it makes the videos more accessible to more people.
When creating Material in the Library, you will have the option to choose whether your file contains AD.
If you do have AD on your ad, please check this option so the correct audio file gets sent to your executive, rather than the AD track.