[Reference:, https://docs.microsoft.com/en-us/azure/azure-sql/database/reserved-capacity-overview, , , , , , Basic Concept: This question tests Azure SQL sizing and purchasing choices, where compute model, scaling behavior, licensing benefits, and cost pattern must be evaluated together., Why D is Correct: The serverless tier automatically scales compute and can pause during inactive periods, making it suitable for intermittent workloads with bursts and idle windows. The scenario asks for: Based on the PaaS prototype, which Azure SQL Database compute tier should you use? That makes Serverless the option that satisfies the required Azure SQL layer and operational outcome., Why A is Wrong: Business Critical provides low-latency local SSD storage and high availability for demanding workloads, but it is usually more expensive than necessary for bursty idle workloads. That design keeps capacity available for a different kind of workload and does not match the cost behavior expected from an idle-and-burst database pattern., Why B is Wrong: Hyperscale is designed for very large databases and fast scale-out storage architecture, not merely for intermittent CPU bursts. That design keeps capacity available for a different kind of workload and does not match the cost behavior expected from an idle-and-burst database pattern., Why C is Wrong: The vCore purchasing model separates compute and storage sizing and supports Azure Hybrid Benefit for eligible SQL Server licenses. It applies to a different Azure data-platform design than the one the question is testing., Verification Note: The original listed answer was A; the corrected answer is D because The prototype shows intermittent spikes with idle periods; the serverless compute tier is designed for intermittent usage and automatic pause/resume cost savings., ]