I've recently downloaded Ubuntu via Virtualbox on my macbook. The installation process was a charm and also I downloaded Virtualbox's extension pack. However, there is no audio whatsoever on the OS. I've tried everything on the web and still couldn't fix the problem.
I'm using Virtualbox 5.1.2 and and latest desktop version of Ubuntu.
This is the Audio menu on my Virtualbox:
I've tried all audio controllers and drivers. None of them work