Answer: Relationship era
Explanation:
Relationship era is defined as the period of time when businesses and organization tend to move towards the long-lasting and reliable relationships with their customers and likelihood.
According to the situation in question, Black Marble Resort is depicting the relationship era of American business's history. Black Marbles resort are trying to establish a relationship with their customers by asking for their feedback, offering discounts etc for long-term..This strategy is stating about the relationship era in which organization were concerned with consumer relationships.