In the Liebrand and VanRun (1985)energy Conservation Game,what Was the Optimal

In the Liebrand and VanRun (1985) energy conservation game,what was the optimal strategy for obtaining the public good?

A) to take small amounts of money on each turn
B) to take gradually larger amounts of money on each turn
C) to take large amounts of money on each turn
D) to take gradually smaller amounts of money on each turn