4. Which one of Marshall's rules suggests why labor demand should be relatively inelastic for public school teachers and nurses? Explain. Shelly's preference for consumption and leisure can be expressed as U(C,L)=(C 100) (L40). Shelly earns $10 per hour after taxes. She also receives $320 worth of assistance benefits each week regardless of how much she works. (a) Graph Shelly's budget line. (b). What is Shelly's marginal rate of substitution when L=100 and she is on her budget line? (c). What is Shelly's reservation wage? (d) Find Shelly's optimal amount of consumption and leisure