The following data are for a series of increasingly extensive flood control projects:
Total cost Total benefit per year per year
Plan A levees $10,000 $16,000
Plan B small reservoir 24,000 36,000
Plan C medium reservoir 44,000 52,000
Plan D large reservoir 72,000 64,000
Refer to the data. For Plan D marginal costs and marginal benefits are:. a. $72,000 and $64,000 respectively. b. $28,000 and $12,000 respectively .c. $24,000 and $18,000 respectively. d. $16,000 and $28,000 respectively.

Wo firms, a and b, each currently dump 50 tons of chemicals into the local river. the government has decided to reduce the pollution and from now on will require a pollution permit for each ton of pollution dumped into the river. it costs firm a $100 for each ton of pollution that it eliminates before it reaches the river, and it costs firm b $50 for each ton of pollution that it eliminates before it reaches the river. the government gives each firm 20 pollution permits. government officials are not sure whether to allow the firms to buy or sell the pollution permits to each other. what is the total cost of reducing pollution if firms are not allowed to buy and sell pollution permits from each other? what is the total cost of reducing pollution if the firms are allowed to buy and sell permits from each other? a. $3,000; $1,500 b. $4,500; $3,500 c. $4,500; $4,000 d. $4,500; $2,500