A: Yes. Any app that allows you to choose an audio input/output can use these virtual cables.
If you only need one audio link (e.g., system audio to a microphone input), the free VB-CABLE is perfect. You need C & D if: vb-cable c d free download
If you need to route audio between 3+ applications, don’t download separate C/D cables—install Voicemeeter Potato. A: Yes
How to use Voicemeeter as Cable C/D replacement: How to use Voicemeeter as Cable C/D replacement:
Result: You effectively have 3 virtual cables without paying for Cable C/D.
No, officially they are not free. VB-Cable C and D are part of the VB-Cables Premium Edition (or the "VB-Cable Hi-Fi / Virtual Audio Cable Pack").