A. #
B. &
C. @
D. $

Explanation:

The @ symbol is a required part of every email address. It separates the username from the email service provider.

Example:

student@gmail.com

Here:

• student = username
• gmail.com = domain name

Without the @ symbol, the email address is invalid.

Key Points:

• Required in every email address
• Separates username and domain
• Makes email delivery possible