What permission is granted to Customers when invited to ChatterGroup?

Universal Containers would like to collaborate with its customers within Salesforce, and has decided to enable the "Allow Customer Invitations" Chatter setting.

What permission is granted to Customers when invited to ChatterGroup?
A . The ability to invite members to groups of which they are a member
B . The ability to @mention accounts of which they are a contact.
C . The ability to request access to public groups
D . The ability to interact with members of their groups

Answer: D

Explanation:

Customers who are invited to Chatter groups can only interact with members of their groups. They cannot invite other members, @mention accounts, or request access to public groups