This must be true. As shown below, by chaining the conditional claims, we see that all contract negotiators must have lied to someone and, in extension, have practiced deception.

This could be false. Practicing deception is not a sufficient condition for anything in our stimulus, which means there are no implications from knowing someone practices deception.

This must be false. Whoever lies to anyone is practicing deception.

This could be false. No information in the stimulus suggests that if someone lies to a contract negotiator they have been lied to by one in the past.

This could be false. We know that anyone who has been lied to has lied to someone, but we don’t know if this conditional relationship goes both ways, as (E) suggests.