Final answer:
Marginal cost is calculated by dividing the change in total cost by the change in output. To find the cost function given the marginal cost and fixed cost, integral calculus should be used to integrate the marginal cost function.
Step-by-step explanation:
We calculate marginal cost by taking the change in total cost and dividing it by the change in output. This is typically calculated using the traditional calculation of marginal cost equal to change in total cost divided by change in quantity. Marginal costs are typically rising, meaning that as production increases, the cost of producing each additional unit goes up.
However, the question asks for the cost function given the marginal cost and fixed cost. In order to find the cost function, we need to integrate the marginal cost function. Since the marginal cost function represents the rate of change of the cost function, integrating it will give us the cost function itself.
Therefore, the correct answer is B) Integral calculus.