Exam PL-100 topic 3 question 62 discussion

You create a flow in a development environment. The flow connects to an internal web service. You plan to move the flow to a test environment and then to a production environment. The flow requires a different URL to connect to the internal web service from each environment.
You must move customizations between environments by using solutions. You must not be required to manually update the URL to the internal web service when you move the flow to other environments.
You need to deploy the solution.
What should you use?