Answer the Question on the Basis of the Following Information

Answer the question on the basis of the following information for four highway programs of increasing scope.All figures are in millions of dollars. $\begin{array}{c}\begin{array}{c}\underline{\text {Program}}\\\text {A}\\\text {B}\\\text {C}\\\text {D}\end{array}\begin{array}{c}\underline{\text {Total Cost}}\\\$ 2 \\6\\12\\20 \end{array}\begin{array}{c}\underline{\text {Total Benefit}}\\\$ 9 \\16 \\21 \\23\end{array}\end{array}$
On the basis of the data we can say that:

A) Program D is the most efficient on economic grounds.
B) Program C is the most efficient on economic grounds.
C) Program B is the most efficient on economic grounds.
D) Program A is the most efficient on economic grounds.