You are studying a "well-run firm" which produces electric motors. You know the price of rotors is $2 per rotor, and the marginal product of rotors...

You are studying a "well-run firm" which produces electric motors. You know the price of rotors is $2 per rotor, and the marginal product of rotors is 1 motor per rotor. You also know the firm uses electricians, and the salary of electricians is $20 per hour. What is the marginal product of electricians in this firm? A) 5 B) 10 C) 15 D) 20 E) none of the above.