Why should you use a subject in an email?

A. To say hello to the person who is getting the email
B. To give an idea of what the email is about
C. To make a joke
D. To type the entire text of the email

We use a subject in an email to give an idea of what the email is about. The Subject Line in an email should be short and descriptive. This allows the person getting the email to have an idea of what will be in the email. This also helps them when looking through their emails to see emails from students who have questions.