Decision Explainer is a feature of the Salesforce Business Rules Engine, which is used in Public Sector Solutions to automate eligibility determination. When an eligibility check is run on an application, Decision Explainer provides a detailed, step-by-step log for that specific record. Agency authorities can use this log to see exactly which rules were evaluated, the input data from the application that was used, and how the final decision (e.g., 'declined') was reached. This provides the necessary transparency and auditability to address the applicant's complaint directly.

A. Debug logs are a developer tool for troubleshooting code execution and are not designed for business users to audit or understand the logic of a specific business rule decision.

C. Testing with data sets is a method for validating the overall accuracy of the rule set during configuration or troubleshooting, not for investigating a specific historical decision on a single record.

D. "Selection Explainer" is not a standard Salesforce Public Sector Solutions feature. The correct tool for explaining decisions made by the Business Rules Engine is Decision Explainer.

1. Salesforce Help, Public Sector Solutions Documentation, "Explain Decision Results with Decision Explainer": "Decision Explainer gives you detailed, step-by-step information about how a business rule produced a result for a specific transaction... For example, a grant-maker can use Decision Explainer to see why a grant application was rejected."

2. Salesforce Help, Public Sector Solutions Documentation, "Set Up Eligibility Determination with Business Rules Engine": "Use Business Rules Engine to create rules that determine whether a constituent is eligible for a program or benefit... Business Rules Engine makes eligibility determination transparent and auditable." This establishes that Business Rules Engine is the underlying technology for eligibility.

3. Salesforce Help, Public Sector Solutions Documentation, "Business Rules Engine": "Business Rules Engine gives you the ability to build and automate complex business rules... Use Decision Explainer to get a detailed explanation of how the rules engine arrived at a result." This confirms the purpose of Decision Explainer in the context of the engine.