What does the graph show?

The graph shows a cost on the y-axis and the number of units on the x-axis. As the number of units increases, the cost per unit decreases.

• Fixed costs per unit: Total fixed costs remain constant regardless of the production volume. However, when these fixed costs are spread over a larger number of units, the fixed cost per unit decreases. This relationship is represented by a downward-sloping curve, where cost per unit approaches zero as the number of units approaches infinity. This matches the graph.
• Standard cost per unit: This is a predetermined cost for a single unit and typically remains constant over a relevant range of activity. It would be a horizontal line.
• Total semi-variable costs: These costs have both a fixed and a variable component. Total semi-variable costs would increase with the number of units, not decrease.
• Variable costs per unit: These costs remain constant per unit regardless of the production volume. They would also be represented by a horizontal line.

Therefore, the graph represents fixed costs per unit.

The correct option is $\text{A}$.