How should the Administrator meet these requirements?

Universal Containers (UC) wants to collaborate with key members of their strategic Partners on deals and marketing initiatives. Sensitive information needs to be shared with confidence, and major opportunities must be tracked. No other Partners can have visibility to this collaboration. Different UC employees have access to different collaboration efforts.

How should the Administrator meet these requirements? Select one or more of the following:
A . Set up Unlisted Chatter groups and make the UC account manager the owner
B . Set up Private Chatter groups and make the UC account manager the owner
C . Build a custom Lightning Component and enable the sharing attribute
D . Configure a Collaboration object with manual sharing

Answer: A