Answer the Question Based on the Following Information for Four

Answer the question based on the following information for four highway programs of increasing scope. All figures are in millions of dollars. The data indicate that

A) there is no highway program that is economically justifiable based on cost-benefit analysis.
B) the marginal cost and marginal benefit of Program A are $2 and $9, respectively.
C) the marginal cost and marginal benefit of Program C are $12 and $21, respectively.
D) program D is optimal because it maximizes the total benefit.