Answer:
Relationship Selling.
Step-by-step explanation:
Based on the scenario being described within the question it can be said that the Drew's success is best explained by the concept of Relationship Selling. This concept refers to a sales technique that focuses on the unique interactions that occur between the salesperson and the current buyer as opposed to the price and product description. Which is what Drew focuses on by caring for the customers needs instead of just trying to sell the product.