What is the purpose of the closing line in a formal email?

Correct answer: To end the email politely and professionally

A closing such as “Yours sincerely,” “Regards,” or “Thank you” brings a formal email to a courteous and professional end. The sender’s name may be written below it. New facts should be placed in the body, the subject is handled by the subject line, and the recipient’s address belongs in the address field, so those options do not describe a closing line.