Why would you consider sending an email to an address that you know does not...

Sending an email to a known non-existent user is a reconnaissance technique used to:

Analyze bounce-back (NDR) messages.

Discover the email server’s operating system, filtering behavior, internal mail routing, and directory structure.

Reveal technologies such as Exchange, Postfix, etc.

From CEH v13 Official Courseware:

Module 2: Footprinting and Reconnaissance

CEH v13 Study Guide states:

“Sending a message to an invalid address can reveal error messages or NDRs that leak internal system details, such as mail server versions, spam filtering technologies, and internal naming conventions.”

Incorrect Options:

A: Not applicable.

B/C: Not the purpose here.

E: Anti-virus testing requires a separate controlled method.