Which tool is used by incident responders to trace back an email during an investigation?

The correct answer is that incident responders typically use tools like SpamCop to trace back an email during an investigation. SpamCop provides valuable services for identifying the origin of potentially malicious emails, allowing responders to report them and analyze the routing of the email to detect potential threats. This tool helps in unraveling the communication paths of email messages, assisting in discerning whether emails are legitimate or linked to spam campaigns or phishing attempts.

The role of this tool is crucial in an incident response scenario because it not only identifies the source of emails but also allows responders to take necessary actions to prevent further malicious communication. By utilizing services like SpamCop, responders can gain insights into the email headers and trace the path back to the sender, which is essential for thoroughly investigating security incidents related to email communications.

Other options do not serve the primary function of tracing back emails within the context of an incident response investigation. Some may provide related functions, but they do not focus primarily on the traceability aspect that is essential for understanding the origins and flow of misleading or malicious emails.