Explanation:

- Option 2: Economies of scale

- Economies of scale refer to the cost advantages that a business can achieve by increasing the scale of production. As production increases, the cost per unit of output typically decreases due to factors like spreading fixed costs, buying inputs in bulk, and operational efficiencies.

- Option 1: Production function

- Describes the relationship between inputs used in production and the resulting output. It highlights how different combinations of inputs produce varying levels of output.

- Option 3: Isocost

- A line representing all combinations of inputs that cost the same total amount. It is used in conjunction with the production function to determine the optimal choice of inputs.

- Option 4: Isoquant

- A curve that represents all combinations of inputs that yield the same level of output. It is often used in economic analysis to evaluate production efficiency.