Which statement correctly refers to economies of scale: 0 a. Economies of scale refer to the shortrun production process only 0 b. Economies of scale imply that the longrun average cost increases as output increases 0 c. Economies of scale is only a technological concept, it does not take into account the cost of inputs 0 d. Economies of scale imply that the long-run average cost decreases as output increases 0 e. Economies of scale refer to the cost of producing several ditferent products simultaneously