PT20.S1.Q06 - besides laying eggs in her own nest

yhchoi1687

http://7sage.com/lsat_explanations/lsat-20-section-1-question-06/
I understand why the answer (D) is correct, but not sure why the answer choice (C) is incorrect. Is it because the answer choice makes an assumption that natural nesting sites will be less crowded than the nesting boxes? I thought this can be a logical conclusion from the passage rather than just assumption. Please explain me why (D) is a better answer choice than (C).

c.janson35

C is incorrect because we have no information about the relative sizes of the nests, only that the boxed nets become crowded. It could be true that the natural nests are very small but that their small size isn't a problem because they are so well hidden, we are just not sure either way because there is no information in the stimulus to support such an assumption.

D is the correct answer because it connects the ideas about visibility and ducks laying eggs. That is, the boxes nests are becoming overcrowded with the "parasitic behavior" of other ducks laying eggs there because they are not as well hidden as the natural nests. While this may not be a 100% validly drawn inference, it is pretty well supported which is what we are looking for in a MSS type question.

Hope this helps!