Minoru is an advertiser at a consumer packaged goods company.He recently ran a campaign where his primary goal was to drive loyalty for his brand'slavender scented laundry detergent.Which metric would be the best indicator of this campaign's success in helping drive loyalty?

Subscribe & Save is the best indicator of loyalty because it signifies repeat purchases and a commitment to the product over time. Customers actively choose to receive the product regularly, demonstrating brand preference and sustained engagement. Purchase rate, while indicating initial sales, doesn't inherently guarantee long-term loyalty; a customer might buy once but not again. Impressions served only measures exposure, not actual customer action or commitment, making it irrelevant for assessing loyalty.