According to the equilibrium principle:

A.market equilibrium exploits all opportunities for individual gain, but may not exploit gains possible through collective action.

B.once a market has reached equilibrium, price will not change.

C.collective action cannot improve on individual action.

D.unregulated markets tend to reach equilibrium prices and quantities without government regulation.

正确答案：market equilibrium exploits all opportunities for individual gain, but may not exploit gains possible through collective action.