@kyoon @Ceci the conclusion here is, "Thus this case shows that sometimes when languages share words that are similar in sound and meaning the similarity is due neither to language relatedness nor to borrowing."
This is a Strengthen with Necessary Premise question so we are looking for the answer choice that (1) strengthens and (2) is necessary to the argument.
(C) does not strengthen this argument so it can be eliminated. It is irrelevant if this is the usually the case. In the stimulus, we are presented with a case of two languages sharing a word that is not due to relatedness.
Hope that helps! Please let us know if you have any other questions.
