The two features of Chatter that would meet CK's business needs are: Set up new public Chatter groups. A public Chatter group is a way to create a collaborative space for users to share information, files, polls, and ideas around a common topic or interest. A public Chatter group can be joined by any user in the organization and can be seen by anyone who has access to Chatter. By setting up new public Chatter groups, CK can enable users to socialize and collaborate around customer accounts and discuss various topics. Use post action on the Account object. A post action is a type of quick action that allows users to create a post on a record's feed or on their own feed. A post can include text, mentions, hashtags, topics, links, files, or images. By using post action on the Account object, CK can enable users to share updates, feedback, or questions about customer accounts and engage with other users who follow the accounts. Set up new private Chatter groups is not a valid feature, as it does not meet CK's business needs. A private Chatter group is a way to create a collaborative space for users to share information, files, polls, and ideas around a confidential or sensitive topic or interest. A private Chatter group can only be joined by invitation and can only be seen by the group members. By setting up new private Chatter groups, CK would limit the visibility and accessibility of the conversations around customer accounts. Use Chatter actions to create tasks to complete is not a valid feature, as it does not meet CK's business needs. A Chatter action is a type of quick action that allows users to create a task from a record's feed or from their own feed. A task can include subject, due date, priority, status, assigned to, etc. By using Chatter actions to create tasks to complete, CK would enable users to track and manage their work related to customer accounts, but not to socialize and collaborate with other users.