Which of the following does not strengthen buyer bargaining power?

Products that are highly differentiated generally enhance a seller's position in the market and weaken buyer bargaining power. When products are unique or distinct from competitors' offerings, buyers have fewer alternatives to choose from, making them less powerful in negotiations. This differentiation can come from branding, quality, features, or customer service, which creates a perception of value that diminishes the likelihood of customers switching to competing products.

In contrast, buyer bargaining power is typically strengthened in situations where there is a threat of backward integration, where buyers can produce the goods or services themselves. It is also strengthened when there are a large number of sellers in the industry, as competition can drive down prices. Lastly, a customer group consisting of numerous buyers may lead to collective bargaining power, which further increases their influence over sellers. All these factors collectively demonstrate why highly differentiated products do not enhance buyer bargaining power, making this choice the correct answer.