Final answer:
The subject of the question is Business, specifically related to customer re-engagement strategies. A goodwill letter would most effectively reactivate business by reminding customers of the benefits of using their charge cards and offering a free gift.
Step-by-step explanation:
Goodwill letters are a tool used by businesses to reconnect with customers and encourage them to start using their services again. In this context, the most effective way to persuade customers to start using their charge cards again would likely be option c: reminding customers of the benefits of using their charge cards and offering a free gift. This method employs a positive incentive and emphasizes the value proposition to the customer, which is usually more persuasive than just pointing out account inactivity or threats of closure.
It is important to maintain a positive tone in goodwill communications and provide an enticement that could lead to increased engagement and loyalty. Offering a new charge card alongside a catalog could also be an effective strategy, as it refreshes the customer's engagement tools, but combining it with the benefits reminder and a free gift could yield the best results.