If the ATC curve has a positive slope, then the MC curve must be

Which of the following paired concepts are equivalent to each other?

a) increasing returns; diseconomies of scale b) increasing returns; increasing costs c) increasing returns; decreasing costs d) increasing costs; economies of scale e) constant costs; economies of scale

Each of the following, except one, is a limitation on collusive behavior. Which is the exception?

a. the market demand curve b. a tit-for-tat strategy c. the threat of prosecution d. incentives for firms to lower prices e. incentives for firms to raise output