When the market price equals or exceeds Noelle’s shut-down price of $10, the minimum average variable cost indicated by point A, she will produce the output quantity at which marginal cost is equal to price. So at any price equal to or above the minimum average variable cost, the short-run individual supply curve is the firm’s marginal cost curve; this corresponds to the upward-sloping segment of the individual supply curve. When market price falls below minimum average variable cost, the firm ceases operation in the short run. This corresponds to the vertical segment of the individual supply curve along the vertical axis.