In a public goods game with 4 players, each player can contribute either $0 or $2 to a common pool. If all players contribute $2, the pool grows to $8 and is split equally among the 4 players. If some players each contribute $2 while the other players contribute $0, the players who contribute get $4 each and the others get nothing. If all players contribute $0, they each get $1. Is there a dominant strategy, and if so, what is it? If there is a dominant strategy, type the amount each player contributed in that strategy as a number (i.e. do not include any words, space, or a $ sign). If there is not a dominant strategy, type NA.