How should the Salesforce Administrator meet this requirement?

Universal Containers has created a Community for its Partners. Community users from the same Partner should be able to hold discussions with each other. Partners will be unable to participate in discussions with other partners.

How should the Salesforce Administrator meet this requirement? Select one or more of the following:

Universal Containers has created a Community for its Partners. Community users from the same Partner should be able to hold discussions with each other. Partners will be unable to participate in discussions with other partners.

How should the Salesforce Administrator meet this requirement? Select one or more of the following:
A . Turn off Portal User Visibility under Sharing Settings
B . Enable super user access for each partners community role
C . Update the internal user record to private under sharing settings
D . Uncheck community user visibility under sharing settings

Answer: D