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.

Juanita and sam attend a beach party and notice that the local beach appears to have a great deal more trash washed up on shore than it did when they were young. the water doesn't appear nearly as clear, and there seems to be less evidence of small water creatures living in the shallows. an afternoon at the local library convinces them that one major cause is the new factory nearby. after some discussion, they decide their next step should be identifying the cause of the changes identifying the problem picketing the guilty factory lobbying their elected representatives to complain about the problem talking to a local environmental group about solutions