Under the five forces model, a differentiation strategy works best when: D$.$ The firm has intangible resources, supplier cost increases can be passed on to the customer, and the differentiation appeal creates customer loyalty. C$.$ The firm has tangible resources, supplier cost increases can be passed on to the customer, and the differentiation appeal creates customer loyalty. B$.$ The firm has tangible resources, supplier cost increases can be passed on to the customer, and equivalent substitutes are readily available. A$.$ The firm has intangible resources, supplier cost increases can be passed on to the customer, and equivalent substitutes are readily available.