The spreadsheet below is a hypothetical example of two proposed uses for a coastal area. The coral reef area will either be protected or mined. A set of costs and benefits is given for a $10-$year period. a$.$ Calculate the net benefit and cost for each period.b$.$ Discount the net benefit for each period into the current period at a discount rate of $5\%$ and $10\%.$c$.$ Calculate the projects net present value of total net benefits at the discount rate of $5\%$ and $10\%.$ d$.$ Which project you would like to choose under the two discount rates? Why?