​Which of the following fields tells the recipient what the message is about? ​

Correct option is C

The correct answer is 3. Subject.

The Subject field of an email provides a brief summary of the message's content. It helps recipients quickly understand the purpose of the email and decide whether to open it immediately or later.  

• To: Specifies the recipient(s) of the email.  
• Date: Indicates when the email was sent.  
• Signature: Usually includes the sender's name, contact information, and sometimes a professional closing.