Conventionally, a valid email ID cannot include which of the following ?

The correct answer is Multiple at signs (@)

Key Points

• Email ID Format: A valid email ID typically follows the format [email protected].
• Multiple @ Signs: ❌ Invalid. An email ID can contain only one @ symbol. Having more than one breaks the standard structure and is not accepted by email systems.
• Multiple Digits: ✅ Valid. Digits 0-9 can be used in any number within the local part of the email.
• Multiple Dots: ✅ Valid if used correctly. Dots can be used in the local part (username), but not at the beginning, end, or consecutively.
• Multiple Underscores: ✅ Valid. Underscores are allowed in the username part of the email.

Additional Information

• Email addresses are governed by RFC 5322 standards.
• Only one @ is permitted, separating the local and domain parts.
• Domain names must follow valid DNS naming conventions.

Hence, the correct answer is: option 4) Multiple at signs (@)