1.   A. Screws are better than nails, and hidden fasteners are better than screws because there are no screw or nail heads showing.

2.   Some deck boards are installed with clips, so there are no nail or screw heads showing.

3.   This is not the best of treatments because a future owner of the house might not take too well to a floor with a bunch of screw heads showing.

4.   This would require screwing or nailing the boards again, this time with nail heads showing, something hardwood floors should not have.