Final answer:
An exclusive dealing agreement is an example of NextGen Electronix Inc.'s monopoly as the sole intermediary for CellDer Inc. products in the city of Erbia. The correct answer is option a.
Step-by-step explanation:
An example of a(n) exclusive dealing agreement is when a wholesaler, like NextGen Electronix Inc., has the exclusive rights to sell products manufactured by a specific company, such as CellDer Inc., in a particular city, like Erbia. This means that NextGen Electronix Inc. is the only intermediary selling CellDer Inc. products in Erbia, giving them a monopoly in that market. Exclusive dealing agreements can have both legal and anticompetitive effects, depending on their purpose and impact on competition.