Assume that a company, UGrowIt, helps people who are new to growing vegetables or have not been successful at growing vegetables in the past. UGrowIt’s employees called Growers travel to people’s gardens and provides gardening advice on how to get started, eliminate pests and insects, or troubleshoot other gardening problems. Each Grower maintains a log of miles traveled as well as time spent at each client. The CEO of UGrowIt wants to know customers’ satisfaction with each Grower using phone interviews. What type of sampling method would be appropriate to make sure that each Grower has adequate representation of customers selected for a phone interview?