A team is developing a serverless application with web frontends communicating to backend services through RESTful endpoints. The application must undergo several testing stages before being deployed to production. What is the BEST method to organize the endpoints to support environment-specific testing without incurring significant operational overhead?
Differentiate between environments by assigning unique tags to the backend services in a single account.
Set up individual accounts for each testing phase and configure the endpoints within each account.
Implement stages in the RESTful service deployment service to represent different environments and leverage environment variables for specific configurations.
Geographically segregate the environments by deploying the backend services and endpoints in corresponding regions.