Final answer:
The best action for a sales associate when a customer complains about the cost of a popular line of T-shirts is to apologize for the inconvenience and offer alternative products that may satisfy the customer's needs.
Step-by-step explanation:
The subject of this question is a business scenario involving customer service and sales strategies. In the scenario where a customer comments that a popular line of white T-shirts seems overpriced, the best option for the sales associate is D) Apologize and offer alternatives. The sales associate can acknowledge the customer's perception and offer additional options that may represent better value or a lower price point. Arguing about price or dismissing the customer's opinion could lead to a negative customer experience and potential loss of the sale.