The total cost of producing one unit is $50. The total cost of producing two units is $75. At a production level of two units, the cost function exhibits

A_________________is a situation where suppliers offer different amounts of products for sale at all possible prices in a market.

Fill in the blank(s) with the appropriate word(s).

Vertical contracts between manufacturers and retailers often aim to

a. Incentivize the retailers to undertake costly activities, which they otherwise may not realize the full benefits of on their own b. Reward the retailer for undertaking the risk inherent in introducing a new product c. Serve as a "signal" of the manufacturer's belief of the likely success of his product d. All of the above