In the Long Run a Company That Produces and Sells

In the long run a company that produces and sells popcorn incurs total costs of $1,050 when output is 90 canisters and $1,200 when output is 120 canisters. The popcorn company exhibits

A) diseconomies of scale because total cost is rising as output rises.
B) diseconomies of scale because average total cost is rising as output rises.
C) economies of scale because total cost is rising as output rises.
D) economies of scale because average total cost is falling as output rises.