DingBat Knobs manufactures door knobs. The graph of the cost function is shown below (Cost is in dollars.): 2800- 2400- 2000 1600- 1200- 800- 400- 10 20 30 40 50 60 70 80 90 100 a. What is the fixed costs to manufacture door knobs? $ b. What are the variable (per knob) costs to manufacture door knobs? S c. What is the cost to manufacture 40 door knobs? S d. Going by just the graph, what is the domain of C(a)? Use inequliaties to answer (and the variable z). Preview e. Going by just the graph, what is the range of C(z)? Use inequliaties to answer (and the variable y). Preview