A Unified Individual is a profile that combines data from multiple sources using identity resolution rules in Data Cloud. A Unified Individual can have multiple contact points, such as email, phone, or address, that link to different systems and records. A consultant can use the following features to display all cases associated with a Unified Individual on a contact record:

Profile API: This is a REST API that allows you to retrieve and update Unified Individual profiles and related attributes in Data Cloud. You can use the Profile API to query the cases that are related to a Unified Individual by using the contact point ID or the unified ID as a filter. You can also use the Profile API to update the Unified Individual profile with new or modified case information from other systems.

Lightning Web Components: These are custom HTML elements that you can use to create reusable UI components for your Salesforce apps. You can use Lightning Web Components to create a custom component that displays the cases related to a Unified Individual on a contact record. You can use the Profile API to fetch the data from Data Cloud and display it in a table, list, or chart format. You can also use Lightning Web Components to enable actions, such as creating, editing, or deleting cases, from the contact record.

The other two options are not relevant for this use case. A Data Action is a type of action that executes a flow, a data action target, or a data action script when an insight is triggered. A Data Action is used for activation and personalization, not for displaying data on a contact record. A Query APL is a query language that allows you to access and manipulate data in Data Cloud. A Query APL is used for data exploration and analysis, not for displaying data on a contact record. References: Profile API Developer Guide, Lightning Web Components Developer Guide, Create Unified Individual Profiles Unit