marginal analysis short answer questions

a) Specify and explain the typical shapes of marginal-benefit and marginal-cost curves.

b) How are these curves used to determine the optimal allocation of resources to a particular product? How are they used to determine the optimal (best) output mix in a production possibilities curve?

c) If current output is such that marginal benefit exceeds marginal cost, should more or fewer resources be allocated to this product? Explain.