The correct answer is D. Price of product.
A firm’s cost curves are determined by the prices of inputs, the technology used, and the level of output. The price of the product is not a factor that affects the firm’s cost curves.
Excise tax is a type of tax that is levied on specific goods or services. It is a form of indirect tax, which means that it is paid by the consumer when they purchase the good or service, but the tax is ultimately borne by the producer. Excise taxes can affect the firm’s cost curves by increasing the cost of inputs.
Prices of inputs are the prices that firms pay for the factors of production that they use, such as labor, capital, and land. The prices of inputs can affect the firm’s cost curves by increasing or decreasing the cost of production.
Increase in productivity is an increase in the amount of output that a firm can produce with a given amount of inputs. It can be achieved through technological innovation, better management, or improved worker training. Increase in productivity can affect the firm’s cost curves by decreasing the cost of production.