hironmentalists back EU emission plans The European Union requires any airline operating to or from an EU airport to participate in the EU cap-and-trade system under which 15 percent of pollution credits for airlines wil be auctioned of and the other 85 percent of credits are being given without charge. Under what conditions would a cap-and-trade system reduce the amount of airline emissions to the efficient quingly? Source The Wall Street Joumal June 30 2011 A cap and-trade system would reduce the amount of airline emissions to the offcent quardly if O A. the EU government finds the quantity at which the marginal social cost of or wavel equals the marginal ben It provides the number of permits such that less than this quartly of Naval is undertaken O B. the EU government finds the quantity at which the marginal private cost of all travel equals the marginal boneit it provides the number of permits such that this is the quaring of travel undertaken Q C. al pollution credits are auctioned off; no pollution credits are given without charge D. the EU government finds the quantity at which the marginal soold cost of all travel equals the marginal it provides the number of permits such that this is the quantity of travel undertaken (3 E. the EU government finds the quantity of which the marginal private cost of air travel equal the marginal benefit it provides the number of permits such that more than this quantity of travel is undertation