Choice (A) is tempting because it is reasonable to think that improving other benefits will help the overall goal of improving retention of the most productive employees. This might very well be true-but the question doesn't ask you to come up with ways to reach the overall goal. Rather, it asks you to strengthen the given argument: that this plan will work in the way described. Choice (A) doesn't say anything about the given plan. It has No Tie to the Argument.