Option 1 -> Profit = Total Revenue - Total Cost; maximizing this difference is the goal of a profit-maximizing firm.
Option 2 -> This represents maximizing losses (TC - TR), which is irrational for any firm.
Option 3 -> Equilibrium occurs where MR = MC, not where MR - MC is maximum; if MR > MC, the firm should increase output.
Option 4 -> Maximizing MC - MR would mean producing where costs far exceed revenue, reducing profits.
Hence, Option 1: The excess of total revenue over total cost is maximum -> A profit-maximizing firm seeks to maximize profit, which is defined as Total Revenue minus Total Cost (π = TR - TC). The firm reaches equilibrium at the output level where this difference is greatest. At this point, the marginal condition MR = MC is also satisfied, ensuring that producing one more or one less unit would not increase profit further. -> correct