I have a service composition with three services. Service A retrieves a list of country codes from a database and keeps this data in memory while interacting with Service B and Service C. However, because Service A is concurrently invoked many times, and because each instance of Service A loads its own copy of the country code data into memory, the demands on the overall infrastructure become too high and performance and reliability are negatively affected. Which service-orientation principle can be applied to help solve this problem? Select the correct answer.