[Reference: https://docs.splunk.com/Documentation/ITSI/4.10.2/SI/GTOverview, A is the correct answer because it is recommended to plan and implement services first, then build detailed glass tables that reflect the service hierarchy and dependencies. This way, you can ensure that your glass tables provide accurate and meaningful service-level insights. Building glass tables first might lead to unnecessary or irrelevant KPIs that do not align with your service goals. References: Splunk IT Service Intelligence Service Design Best Practices]