Answer:
a. Telling someone to keep quiet
Step-by-step explanation:
Communication refers to the relay of information between two or more people. Communication can take many forms and can be passed through various means or channels. Telling someone to keep quiet is a form of command or instruction which is meant to be obeyed.
It is used for children to regulate their behavior. When used on adults who do not like being regulated, it might come off as offensive.