For workers in Group H (high-skill workers), the cost of attaining an educational level y is CH(y) = $10y; for workers in Group L (low-skill workers), the cost of attaining an educational level y is CL(y) = $15y. Employees will be offered $60 if they have y y, where y is an educational threshold determined by the employer. They will be offered $20 if they have y < y. a) Find if in equilibrium, education can be used as a market signal of the worker's skill