Which metric would best reflect success in driving loyalty?

The selected answer Subscribe and Save is correct because it directly reflects success in driving loyalty. "Subscribe and Save" is a program that encourages customers to make recurring purchases of products, which fosters long-term relationships and repeat buying behavior. When a customer subscribes to regularly receive a product, it indicates that they are not only loyal to the brand but also committed to purchasing over time. This metric is a strong indicator of customer retention and loyalty, as it shows that consumers are repeatedly engaging with the brand and its products. In contrast, metrics like "Add to Cart" and "Impressions" are more focused on initial interest or awareness rather than ongoing customer loyalty.