allows) users to communicate privately, one-to-one. A. Workgroup messaging services B. Chat rooms C. Direct messaging D. Branded channels E. Communities of interest

C. Direct messaging

Explanation:

The direct messaging is considered to be private communication in which the sender and the receiver directly communicated with each other. It is also known as one to one communication

In this, no one is there to interpret their communication. It involves one sender, who sends the message and one receiver who received the message sent by the sender.  

Therefore, other forms of communication do not represent private communication

more than 1 person for sure