I'm using Vegas Pro 16 to edit the audio for our video podcasts. We're using Audacity to convert the audio recording of the interviewer. To convert the video recording (and Audio) we're using Handbrake. Both converted files are then imported into Vegas Pro 16 where I want to remove the audio stream of the interviewer from the video file, so that we can match it with the the audio recording from Audacity.

However, when we right click on the audio stream from the video and select ‘Channels’ none of the options are available to select.  We've also tried ungrouping them, but none of those options are available under that field either. 

Does anyone have any idea what I might be doing wrong?