Elinor Ostrom Won the 2009 Nobel Prize in Economics for Her

Elinor Ostrom won the 2009 Nobel Prize in economics for her research showing:

A) social norms can sometimes be powerful enough for commonly held property to be managed extremely well.
B) social norms are not an effective solution for the management of commonly held property.
C) that privatization of public goods is the most effective solution to market failure associated with commonly held property.
D) government provision of public goods is the most efficient solution to the tragedy of the commons problem.