To what does "message repudiation" refer to what concept in the realm of email security?

A.
Message repudiation means a user can validate which mail server or servers a message was passed through.

B.
Message repudiation means a user can claim damages for a mail message that damaged their reputation.

C.
Message repudiation means a recipient can be sure that a message was sent from a particular person.

D.
Message repudiation means a recipient can be sure that a message was sent from a certain host.

E.
Message repudiation means a sender can claim they did not actually send a particular message.

Explanation:
A quality that prevents a third party from being able to prove that a communication between two other parties ever took place. This is a desirable quality if you do not want your communications to be traceable.
Non-repudiation is the opposite quality–a third party can prove that a communication between two other parties took place. Non-repudiation is desirable if you want to be able to trace your communications and prove that they occurred. Repudiation Denial of message submission or delivery.