4. A monopolist has a cost function given by c(y) = y and faces a demand curve given by P(y) = 120 - y. (@) What is its profit-maximizing level of output? What price will the monopolist charge? (b) If you put a lump sum tax of $100 on this monopolist, what would its output be? (c) If you wanted to choose a price ceiling for this monopolist so as to maximize consumer plus producer surplus, what price ceiling should you choose? (d) How much output will the monopolist produce at this price ceiling? (@) Suppose that you put a specific tax on the monopolist of $20 per unit output. What would its profit-maximizing level of output be