A restaurant's trading area is A. the 5-mile radius surrounding its location B. the 10-mile radius surrounding its location C. the 15-mile radius surrounding its location D. the 20-mile radius surrounding its location

The answer is "Option A".

Explanation:

Its trading area for something like a restaurant was its area that comprises its customers' surrounding populations. It depends on the location of its restaurant, and there is some area consisting of customers, people, employees, etc. These citizens become part of the business area of its restaurant.