What Is the Essential Feature of Enterprise Social Media

What is the essential feature of enterprise social media?

A) the capacity to record, store, and share ideas that can be accessed by all organizational members
B) the capacity to record, store, and share ideas that can be accessed by the general public
C) the capacity to record, store, and share ideas that can be accessed by an organization's customers
D) the capacity to record, store, and share ideas that can be accessed by the senior management of an organization
E) the capacity for upward, downward, and horizontal communication that is available to all organizational members