Refer to the table to answer questions 1-3. Units TR TC MC MR Prot 0 20 1 30 2 35 3 45 4 60 5 90 6 130 1. Fill in the TR, MC, and MR columns in the table if the price of the product is $20. 2. What is the optimal output rule used to maximize a rm's prot? 3. What level of output will maximize this rm's prot? Use marginal analysis to explain (you can check your answer using the prot column in the table)