2. Consider some activity Afor which the total benefits and total costs associated with the different levels of A are measurable in dollars as tabulated below. Level of Activity A a. 0 1 2 3 4 5 6 7 8 9 10 11 12 Total Benefit 0 $31.75 60.75 87.25 111.40 133.60 154.60 174.10 192.10 209.20 223.45 235.90 247.10 Total Cost 0 $2.50 6.25 11.25 18.00 26.30 35.40 49.20 66.95 88.95 114.95 145.45 180.05 Marginal Benefit XX Marginal Cost XX Net Benefit Calculate marginal cost and marginal benefit. The optimal level of activity A is A* =