The point on the supply curve at which a firm earns only normal profit is called _________

The correct option is Break-even point.

To understand why this is correct, let us break down the concepts of normal profit and the break-even point step-by-step:

1. Understanding Normal Profit:
In economics, a firm's total cost includes both explicit costs (out-of-pocket expenses like wages and rent) and implicit costs (the opportunity costs of the resources owned and used by the firm). When a firm's total revenue ($\mathrm{TR}$) is exactly equal to its total cost ($\mathrm{TC}$), its economic profit is zero. This state of zero economic profit is referred to as earning normal profit. Normal profit is the minimum level of profit necessary to keep the firm operating in its current line of business in the long run.

2. Defining the Break-Even Point:
The break-even point is the specific point of production on the supply curve where the firm's total revenue equals its total cost. At this point, the price ($P$) of the good is exactly equal to the average total cost ($\mathrm{ATC}$) of production. Since price equals average total cost, the firm is covering all of its expenses (both explicit and implicit) but is not making any extra (supernormal) profit. Therefore, the point on the supply curve at which a firm earns only normal profit is called the break-even point.

3. Analyzing the Other Options:
• Average Profit: This is the profit earned per unit of output sold, calculated as total profit divided by quantity. It is a measure of profitability, not a specific point on the supply curve.
• Long Run Average Cost: This represents the per-unit cost of producing output when all inputs are variable. While it is related to long-run equilibrium, the curve itself is not a single point where only normal profit is earned.
• Fixed Cost: This is the cost that does not change with the level of output produced (such as factory rent). It does not define a point of profit representation.