Identify the Question Stem: The word assumes indicates that this is a Find the Assumption question.
Deconstruct the Argument: Inorganic pesticides stay on the surfaces of produce (fruits and vegetables) for several days, but organic pesticides dissipate (essentially, evaporate) after a few hours. The author concludes that, in order to avoid ingesting toxins, it's necessary to wash produce that was sprayed with inorganic pesticides, but that this action is not necessary if organic pesticides were used.
Pause and State the Goal: On Assumption questions, your goal is to find something that the author must assume to be true in order to draw the given conclusion. In this case, the author is assuming that produce sprayed with organic pesticides doesn't need to be washed but produce sprayed with inorganic pesticides does need to be washed. First of all, the author must be assuming that there are in fact toxins present in the pesticides. The author must also be assuming that the organic pesticides don't somehow leave behind toxins when they dissipate.
Work from Wrong to Right:
(A) This is tempting! It's true that the author is assuming that people will know whether the produce was sprayed with organic or inorganic pesticides (so that they know whether they need to clean it). But this choice talks merely about the origins of the produce—that is, where the produce was grown. It's possible to be told whether the produce is organic without being told which specific farm it came from. (And knowing the farm that it came from doesn't necessarily tell you whether it's organic.)
(B) If anything, the author is assuming the opposite of this choice: that produce sprayed with organic pesticides does not reach consumers until enough time has passed for the pesticides to dissipate from the skin of the product.
(C) The argument is concerned with how different types of pesticides can be removed from the produce. It doesn't claim that one farm can't use both types of pesticides.
(D) CORRECT. Both types of pesticides are sprayed on the surface of the produce. The author claims that washing the inorganic pesticide produce is sufficient to remove any toxins. Further, the organic pesticide is described as leaving the surface of the produce free of pesticide residue after it dissipates. So the author is assuming that the pesticides can't actually penetrate beneath the surface of the skin. If they can penetrate, then it's possible that toxins could remain beneath the surface of the skin even after washing the skin or waiting for natural dissipation.
(E) The conclusion of the argument is not concerned with the cost of produce; it's concerned solely with whether toxins are present.
The correct answer is (D).
