You design the security access to the Power Platform solutions. 
Please select correct statements about solutions access for external users.

Answer options:

A.You can make a guest user a co-owner of the Power Apps app
B.External user must be added to Azure AD before you can share the Power Apps with the user
C.All Power Platform connectors support guest access
D.Each guest user needs to have a Power Platform license to use a shared app
E.Power Apps portal requires Azure AD account for the authenticated external users

Correct Answers: B and D 
Power Apps provides an easy way to share your apps with people in your tenant. You can share it with different groups as well. To share apps with external users, you need to add users as guest users to Azure AD. Then you can search and select a guest user when you share an app (Number 1). You also need to assign an appropriate Power Platform license to each guest user. By sharing the app with a guest user, you also share the data source connectors that the app uses (Number 3). In model-driven and portal apps, the users` access is limited to the Dataverse data (except embedded canvas apps). But if you are sharing a canvas app, not all connectors support guest users. Guest users can use only connectors that don`t require any Azure AD authentication. 
Power Apps provides two access level permissions you can assign to the users during canvas app sharing: Co-owner — individuals or groups with this permission can run, edit, and share the app. But they cannot delete it or change the app’s owner.
User — individuals or groups with this permission can run the app. But they cannot change it.
By default, all users have User permissions. You can promote them to Co-owner status during the app`s sharing. But you cannot make a guest user an app’s co-owner (Number 2). 

If you assign the permissions to the security group, everybody will have the assigned permission level. Additional to the group assignment, you can promote individuals in the group to another level. If you share your app with a large group, the best way is to use Azure AD groups. 
The Power Apps portal application is designed for sharing the Dataverse information with external users. You don’t need to add these users to the Azure AD. A portal provides a variety of third-party identity providers, like OAuth2 (Microsoft, Twitter, Facebook, Google, etc.), OpenID (Azure AD, Azure AD B2C), and WS-Federation and SAML 2.0 (AD on-premises). Azure AD is one of them. Portal administrators can enable/disable Identity providers and set them as default on the portal’s Authentication Settings panel. 
For each authenticated user, a portal creates a contact record in the Dataverse database. It also assigns a web role. The role defines a user`s access to portal resources.
Option A is incorrect because you cannot make a guest user a co-owner of the Power App.
Option C is incorrect because guest users can use only connectors that do not require any Azure AD authentication.
Option E is incorrect because the Power Apps portal does not require an Azure AD account for the authenticated external users.
For more information about guest sharing of the Power Apps, please visit the below URLs: 

https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/share-app-guests
https://docs.microsoft.com/en-us/powerapps/maker/portals/configure/configure-portal-authentication
https://docs.microsoft.com/en-us/powerapps/maker/model-driven-apps/share-model-driven-app