You can access the diagrams for the argument and for the reasoning as to why answer choice (A) is correct in the thread above from 9/23/14. Let's go over the other answer choices:
(B): Not everyone who practices deception is lying to someone.
(B): PD-some-L2A L2A-some-PD
Remember, "not everyone" does not mean "no one." Not everyone merely means at least one person is not participating. So, we look at it as a "some." The argument does not deal with quantifiers, so our correct answer cannot be a quantifier statement.
(C): Not everyone who lies to a contract negotiator has been lied to by a contract negotiator.
Again we are dealing with a "not everyone," which is a "some." For the same reason as answer choice (B), therefore, this is not the correct answer.
(D): Whoever lies to a contract negotiator has been lied to by a contract negotiator.
(D): L2CN ==> BL2CN not BL2CN ==> NOT L2CN
Answer choice (D) is not correct because the argument does not deal with what happens when a contract negotiator lies to someone or when someone lies to a contract negotiator.
(E): Whoever lies to anyone is lied to by someone.
(E): L2A ==> BL2 not BL2 ==> not L2A
Answer choice (E) is the incorrect reversal of P3. "BL2" is the sufficient condition of the sentence, not the necessary. Remember, to create an accurate contrapositive, we must reverse and negate. Answer choice (E) has merely reversed P3, but not negated.
Thus, answer choice (A) is the correct answer.
Hope that clears things up! Please let us know if you have any other questions.
