The choice of answers are incomplete and as such i will answer your question as much as i can.
Answer:
creating (and maintaining) long-term customer relationships.
Step-by-step explanation:
From the question above, Gina's retail store policy which reads "Without our customers, we don't exist", shows that for Gina stores to remain open, it requires the patronage of its customers.
With this idea embedded in the minds of Gina and her staff, creating and maintaing long term customer relationships are very important as it ensures that customerskeep coming back to Gina's store to patronise her.
A few ways to create and maintain long term customer relationships include great customer service, service delivery, etc.
Cheers.