Which concept is specifically written in the bill of rights? g?

The right of the people to keep and bear arms, choice (d), is specifically stated. This would be the gist of the text of the 2nd Amendment, which also allows for the ability for states to keep "well-regulated militias." The ability of the person to "own" the arm (and what type), though, is less clear, since this is not specifically mentioned in the text of the amendment.