The short-run aggregate supply curve is upward sloping because:_______
a. the higher prices allow the firm to hire more workers by offering higher wages, thereby increasing productivity and profits.
b. the money wage rate (and other input prices) remains constant so the higher prices makes it profitable for firms to expand production.
c. firms can increase their profits by increasing their maintenance.
d. each firm must keep its production up to the level of its rivals, and some firms will expand production as the price level increases.
