The local mall's food court has a dozen different types of fast food/restaurants. All the business owners decides to work together to lower the cost of napkins, utensils, and cleaning materials They do this by creating bulk buys through a particular supplier. This would be an example of which Porter's Five Forces

Bargaining power of customers

Explanation:

When the customers sit together and work as a single entity for combined objective they can force the supplier to lower its cost and this lowering of cost by increase in decision altering power of the supplier is bargaining power of customers. If the customer is not coming to you because they have alternatives then the supplier goes to customer with a discounted offer. So this scenario tells about the bargaining power of customer that forces the supplier to deliver the same product at a lower cost.

answer; (covenant); good luck