A public sector agency is leveraging the Business Rules Engine for its Licensing & Permitting implementation. The agency needs to allow multiple…

To calculate a total fee from multiple permit records using the Business Rules Engine (BRE), the primary tool is an Expression Set. The correct approach involves two key actions. First, an Aggregate step is added to the Expression Set's logic flow. This step is specifically designed to process a collection of records. Second, this Aggregate step is configured to use the SUM function on the fee field of the permit records. This aggregation is typically placed at the end of the Expression Set to ensure all individual permit data has been processed before the final total is calculated.

A. A Lightning Component involves custom code, which is unnecessary as the Business Rules Engine provides a standard, configurable feature for this exact requirement.

C. Permission Sets are for managing user access and security, not for defining the business logic or calculations within the Expression Set itself.

1. Salesforce Help, Public Sector Solutions Documentation, "Aggregate Element in Business Rules Engine." This document details the use of the Aggregate element (step) to perform functions like Sum on a list of sObjects, which directly supports using a SUM function to total permit fees.

2. Salesforce Help, Public Sector Solutions Documentation, "Expression Set Step Types." This guide lists "Aggregate" as a standard step type used to "aggregate a list of values and return a single value," confirming it as the correct component for this use case.

3. Salesforce Help, Public Sector Solutions Documentation, "Build an Expression Set." The procedural guide for building Expression Sets illustrates that steps like Aggregate are added to the canvas, often sequentially. Placing the final summation step at the end of the logic is a standard design pattern.