The one you want to use. Follow your intuition and do what you feel comfortable with and ideally with which have a track record of accuracy.
For me, I’d use the Quareia deck that has become my go-to deck since I got into it earlier this year, superseding 30 years working with my old Tarot deck. But I can’t expect everybody to do what I’d do. If you prefer muscle testing, or pendulums, or runes, that’s all good too.