This is a valid argument, unlike the stimulus. (A) uses a valid contrapositive: it switches the initial relationship (if you ask for favors, you are refused) and negates both sides. By contrast, the stimulus negates both sides of the relationship, but doesn’t switch them.

This is a different flaw. (B) assumes that, because something was true in the past, it must be true in the future. By contrast, the stimulus mistakenly assumes that a negation of both sides of a conditional relationship is valid.

If this is a flawed argument, it’s not the same flaw as the stimulus. The conclusion of (C) is an “ought” statement: students should not try to improve their skills. By contrast, the stimulus’ conclusion is an “is” statement: nonrational, emotional appeals will persuade people.

This is the wrong flaw. (D) mistakenly assumes that increasing a necessary condition must increase a sufficient condition. An analogous argument would be: If you don’t eat food, you will die. Therefore, the more food you eat, the longer you’ll live. By contrast, the stimulus mistakenly assumes that a conditional statement is still valid when both sides are negated.

(D) would be correct if the conclusion were: “Therefore, a person who does have positive letters of reference will get a good job.”

(E) concludes that, if people read well-written directions, they will learn to program a computer. This is because, if people don’t read well-written directions, they won’t learn how to program a computer. This is the same flaw as the stimulus: assuming that a conditional statement is still valid after negating both sides. In this case, it’s possible that people who read well-read directions are still unable to program.