I want to run 4 x 10-gauge conductors (Neutral, Ground, 2 Hots) from a
generator inlet box at the back of the house to a transfer panel in the
basement -- approx. 25 ft.

They will run parallel to the joists most of the way. Should I use
individual THHN conductors in conduit (metal? PVC? I understand that
3/4" is an appropriate size), or can I use 10-3WG NM-B stapled to the
sides of a joist?

Perce