For an incentive to work,it must be at least as large as B+C+D, which is the additional profit earned by planting,given the higher price P.The cost to the government is therefore at least B+C+D. Finally, APS=A-C+payments for not producing=A-C+B+C+D=A+B+D the change in total welfare APS+ACS-payments for not producing=A+B+D-A-B-B-C-D=-B-C For an incentive to work, it must be at least as large as B + C + D, which is the additional profit earned by planting, given the higher price Ps . The cost to the government is therefore at least B + C + D. Finally, △PS = A - C + payments for not producing = A – C + B + C + D = A + B + D the change in total welfare △PS + △CS - payments for not producing = A + B + D -A-B - B - C - D = - B - C