What type of appeal is used when emphasizing the benefits of switching to a lighter envelope to save on postal rates?

The correct answer highlights a Bargain Appeal, which is a persuasive technique that emphasizes cost savings and practical benefits. In this case, advocating for a lighter envelope focuses on how making the switch can reduce postal rates. This appeal effectively addresses the audience's interest in saving money, showcasing the tangible advantage of changing their current practice. By highlighting the cost-effectiveness of using a lighter envelope, this strategy directly engages the audience's desire for better financial management.

The appeal focuses on rational decision-making based on economic benefits, making it straightforward and functional, rather than relying on other emotional or social factors that might be found in the other options.