Universal Containers wants to set a custom field on the messaging session based on the...

A Flow (specifically, a record-triggered or platform event–triggered Flow) can be configured to automatically populate or update a custom field on a Messaging Session record when a session is created. The Flow can reference session attributes, such as the originating URL or other metadata, to set the correct value dynamically.

Option B (Einstein Bot) can capture conversation input but cannot directly write or update Messaging Session fields.

Option C (Macro) automates agent actions in the console, not background data population or automation on messaging objects.

Referenced Salesforce Materials:

Service Cloud Consultant Exam Guide – Interaction Channels Domain.

Salesforce Help: “Automate Messaging Session Field Updates with Flow.”

Salesforce Spring ’24 Release Notes – Messaging Automation Enhancements.