Which of the following statements is correct? O The long-run total cost curve is the total of all the short-run total cost curves. O The marginal cost curve intersects average variable cost (AVC) and average total cost (ATC) at the maximum of ATC and AVC. O The long-run average total cost curve must be the lower envelope of all of the firm's short-run average total cost curves. O In the short run where capital is fixed, to minimize the cost, the necessary condition is the technical rate of substitution equals to input price ratio.
