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.