Select the INCORRECT condition for profit maximisation in the perfect market.

1. The price must equal to MC.
2. Marginal cost must be non-decreasing.
3. Price must be less than the average cost.
4. Price must be greater than the average cost.

Option 1 -> This is correct. In perfect competition, profit maximization occurs where Price = Marginal Cost (P = MC).

Option 2 -> This is correct. The MC curve must be rising (non-decreasing) at the equilibrium point to satisfy the second-order condition for profit maximization.

Option 3 -> This is incorrect. If P < AC, the firm makes losses. This is NOT a condition for profit maximization.

Option 4 -> This is also not a necessary condition, but describes a profit-making scenario, not a loss scenario like option 3.

Hence, Option 3: Price must be less than the average cost -> For profit maximization in perfect competition, the essential conditions are: (1) P = MC and (2) MC is rising. Whether P is greater than, equal to, or less than AC determines if the firm makes profit, breaks even, or incurs losses - but profit maximization occurs at P = MC regardless. Option 3 is incorrect because it suggests a loss-making condition (P < AC) as necessary for profit maximization, which is false. A firm can maximize profit even when P > AC, P = AC, or in the short run when P < AC (but P > AVC). -> correct