Option 1 -> Equilibrium requires MR = MC, not MR = AC; AC rising is not the equilibrium condition.
Option 2 -> AR = MR = MC is correct, but MC must be rising, not falling, for stable equilibrium.
Option 3 -> AR and MR cannot equal TC as TC is a total measure while AR and MR are per-unit measures.
Option 4 -> Under perfect competition AR = MR = Price; equilibrium requires MR = MC with MC rising.
Hence, Option 4: AR = MR = MC and MC must be rising -> Under perfect competition, the firm is a price taker where AR = MR = Price. The producer equilibrium occurs at MR = MC (first-order condition for profit maximization). Additionally, MC must be rising at the equilibrium point (second-order condition) to ensure stable equilibrium. If MC were falling, the firm could increase profits by producing more units, meaning it wouldn't be at true equilibrium. The rising MC ensures that any deviation from the equilibrium output level will reduce total profit. -> correct