One of the three shops on campus that sell university logo clothing has found that if it sells a sweatshirt for $30 or more, the other two shops keep their prices constant and the store loses revenues. If, however, the shop reduces its price below $30, the other stores react by lowering their prices. What kind of market structure does this store face? A. Oligopoly. B. Monopoly. C. Perfect Competition. D. Monopolistic Competition. If the store's marginal costs fluctuate up and down very slightly, how should the store adjust its prices? A. Prices should fluctuate with marginal cost. B. Prices should fluctuate if revenues fall. C. Prices should stay the same since the store expects lost revenue whether it raises or lowers the price. D. None of the above.