Given the Information in the Following Table,________ Is the Cost-Effective

Given the information in the following table,________ is the cost-effective way to reduce the phosphorous concentration in the Bay of Quinte. $$\begin{array} { | l | c | } \hline \text { Strategy } & \begin{array} { c } \text { Cost (\$ thousands) per microgram/ } \\\text { litre reduction in phosphorus }\end{array} \\\hline \begin{array} { l } \text { Reduction in phosphorus inputs from agricultural } \\\text { runoff }\end{array} & 2,033 \\\hline \text { Alum treatment of sediments in the bay } & 2,000 \\\hline \begin{array} { l } \text { Treatment of wastewater from water treatment } \\\text { plants }\end{array} & 98 \\\hline \text { Tertiary treatment at sewage treatment plants } & 1,078 \\\hline\end{array}$$

A) reduction in phosphorus inputs from agricultural runoff
B) alum treatment of sediments in the bay
C) tertiary treatment at sewage treatment plants
D) treatment of wastewater from water treatment plants