A dog groomer wants to gather information about how often dog owners have their dogs groomed. She decides to take a sample from her local veterinarian's office, which provides an alphabetized list of all clients who bring in dogs. The
dog groomer randomly selects one of the first 10 clients, and calls that client and every 10th client after that on the list
to inquire about dog-grooming habits. What kind of sample is this?