In the Long Run,the Shape of the Aggregate Supply Curve

Multiple Choice

In the long run,the shape of the aggregate supply curve is

A) upward-sloping, because output can be increased only at higher costs
B) horizontal, because all inputs are variable
C) horizontal, because markets become perfectly competitive
D) vertical, because further expansion of output is unprofitable, regardless of prices
E) downward-sloping, because firms must ultimately charge lower prices in order to sell more output