Three sites (A, B & C) are being considered for flood control dams. The three construction costs are $10 million, $12 million and $20 million; and the annual maintenance costs are expected to be $15,000, $20,000 and $23,000 respectively for sites A, B and C. In addition, a $75,000 refurbishing expenditure will be required every 10 years at each site. Every year without the dams, $2 million in flood damage occurs. It is projected that dam A, by itself, would reduce the annual damage to $1.6 million. Similarly, Dam B would reduce the damage to $1.2 million, and Dam C to $0.77 million. Since the dams would be built on different branches of a large river, any one or all of the dams could be constructed, and the flood damage reductions would be additive. The planning interest rate is 5% per year, and the dams would be considered permanent.

a. Are the dam options Mutually Exclusive or Independent alternatives? b. Determine which dams, if any, should be built on the basis of their Standard Benefit Cost Ratios.