On contracts and transactions costs. The marginal benefits of a contract the Weyer Corporation could make with the Steuben Company for brackets that are used in producing industrial windows is $556 per bracket per month while the marginal cost of such a contract is MC= 300 + L^2 per bracket, with L being contact length in months. What is the optimal length of a contract , L, which Weyer could make with steuben? Derive and explain your answer.