Comprehensive and Detailed Explanation From Exact Extract:

The case-instance-first design pattern in Pega, as described in Pega Academy’sApplication Design Missionand thePega Certified Lead System Architect Study Guide, is used when a case instance must exist before related actions or data updates occur, ensuring that all actions are tied to a specific case context.

Option A (Correct): In a sports competition management system, assigning users to an existing competition case to provide a score requires the case-instance-first pattern. The competition case must exist to provide the context for scoring, aligning with Pega’s case-centric design, per theCase Designmodule.

Option B (Incorrect): Event schedule preparation with an approval process does not strictly require a case-instance-first pattern. The schedule could be managed as a data object or standalone process, not necessarily tied to a pre-existing case, as noted in theProcess Designguidelines.

Option C (Correct): Capturing a patient’s medical history before diagnostics and scheduling requires a case-instance-first pattern. The patient case provides the context for storing history and coordinating subsequent actions, a common healthcare use case, per theHealthcare Application Designmodule.

Option D (Incorrect): Browsing products and adding to a cart does not require a case instance until checkout. These actions are typically data-driven (e.g., cart as a data object), not case-driven, per theE-commerce Designguidelines.