which of the following statements is true of market failures?
a. Market failures bolster the ability of economic markets to achieve a sound environmental policy. 
b. Ad hoc attempts to repair market failures have proved to be environmentally adequate. 
c. Market failures occur when abundant markets exist to create a price for important social goods. 
d. Sacrificing the first generation of public goods as a means for gaining information on market failures is an ill-advised strategy.