
Explanation

In the Users section, specify the users that the access review applies to. Access reviews can be for the members of a group or for users who were assigned to an application. You can further scope the access review to review only the guest users who are members (or assigned to the application), rather than reviewing all the users who are members or who have access to the application.

Present Use Case:
Group2 is a member of Group1 and User3 is the owner of Group1 So User3 can review both Group 1 and 2.
But for review the scope says only Guest.
Solution:
User1 is a member not a guest so 1st statement ==> NO
UserA is member not the guest so 2nd statement ==> No
UserB is a guest so 3rd statement ==> Yes
Reference:
https://docs.microsoft.com/en-us/azure/active-directory/governance/create-access-review