This question: 2 point(s) possible Describe what fixed costs and marginal costs mean to a company. Choose the correct answer below. O A. Fixed cost is the rate of change of cost C(x) at the level of production x and is equal to the slope of the cost function at x. Marginal cost is the constant for a particular product and does not change as more items are made. O B. The number of units at which revenue just equals cost is the fixed cost. Marginal cost is the constant for a particular product and does not change as more items are made. O C. Fixed cost is the constant for a particular product and does not change as more items are made. The number of units at which revenue just equals cost is the marginal cost. D. Fixed cost is the constant for a particular product and does not change as more items are made. Marginal cost is the rate of change of cost C(x) at the level of production x and is equal to the slope of the cost function at x