Answer:
B. An unofficial means of communication.
Step-by-step explanation:
Grapevine is the network or channel that is used as a means of informal communication in an organization. This informal means of communication is based off the passing of information that is controlled or managed by the people and not the high authority.
In this form of communication, the flow of information has no set rules and can be passed from anyone. It doesn't necessarily come from the head to the lower employees or goes in one specific direction. Rather, it is passed from one point to another, irrespective of who or what position the other person holds.