Final Cut Pro X exporting to work with Windows Media Player

I recently had clients say they cannot here audio when playing videos I've exported from FCPX.

In both instances the clients have been using Windows Media Player and I've exported a .mov file for them

They have not been able to install quicktime on there work machines so I need a good setting that I can export using so they don't have any playback issues with the audio.

Does anyone have any suggestions as to what Audio settings work with Windows Media Player, I dont' have access to a windows machine to test.

Cheers Dai