a. Pieces move forward on a grid.
b. The first player without pieces wins.
c. The game is played by two to four players.
d. A piece may only move into an unoccupied square.
The right answer for the question that is being asked and shown above is that: "d. A piece may only move into an unoccupied square." a rule in checkers is that d. A piece may only move into an unoccupied square.
