GMAT Sentence Correction (SC) | Re: Though once powerful political forces, labor unions have

That’s a good explanation by chetan2u of why B is better than D. Often eliminating unnecessary words can enable you to see the correct option more quickly. In this case “some analysts claim” was eliminated. Even if you didn’t notice this, you may have chosen B over D because it is shorter and simpler. Notice the placement of “which” next to “influence” in A, C and E. This is incorrect as “which” does not refer to “influence”.

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