In a perfectly competitive market, what is the market supply in the short run? Question content area bottom Part 1 The market supply in the short run is _______. A. illustrated as a curve that is the vertical sum of the marginal cost curves of all the firms in the market B. calculated as the sum of the quantities supplied by all firms in the market at prices above their shutdown price C. calculated as the sum of the quantities that firms produce when they maximize economic profit at each market price D. illustrated as a curve that is the vertical sum of all the supply curves of the firms in the market when the number of firms remain constant