B: Customer self-service portal: A customer self-service portal enables customers to access self-service knowledge, support resources, view the progress of their cases, and provide feedback.
Note: Based on the selected environment in Power Apps, you can create a Dataverse starter portal or a portal in an environment containing customer engagement apps (Dynamics 365 Sales, Dynamics 365 Customer Service, Dynamics 365 Field Service, Dynamics 365 Marketing, and Dynamics 365 Project Service Automation).
E: Omnichannel for Customer Service offers a suite of capabilities that extend the power of Dynamics 365 Customer Service Enterprise to enable organizations to instantly connect and engage with their customers across digital messaging channels.
Reference:
https://docs.microsoft.com/en-us/powerapps/maker/portals/portal-templates
https://docs.microsoft.com/en-us/dynamics365/customer-service/embed-chat-widget-portal

Scenario: IT specialists want to design Power BI reports. They need to understand the underlying table relationships of the system.
Business process modeler (BPM) in Microsoft Dynamics Lifecycle Services (LCS) is a tool that you can use to create, view, and modify repeatable implementations that are based on business process libraries. BPM helps you align your business processes with industry-standard processes that are described by the American Productivity & Quality Center (APQC) Reference:
https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/dev-itpro/lifecycle-services/bpm-overview

Scenario: Information about each machine produced must be transferred to Dynamics 365 Field Service.
Use the Microsoft Dataverse connector when connecting to the Microsoft Dataverse used for Microsoft Dynamics 365 Sales, Microsoft Dynamics 365 Customer Service, Microsoft Dynamics 365 Field Service, Microsoft Dynamics 365 Marketing, and Microsoft Dynamics 365 Project Service Automation.
Reference:
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/connections/connection-dynamics-crmonline