Modifiers are words, or sentences even, that can change, or clarify, the meaning of a specific words. Usually modifiers are either adverbs or adjectives that if removed from the sentence itself will not affect the general comprehension of the words, but if used, they expand the information that will further clarify a point. Usually, as said before, modifiers tend to be just words, descriptive in nature, which is why the most commonly used are adverbs and adjectives. But there is another classification, which is, modifier clauses, which are sentences that modify, or rather, clarify, a concept, or word. In this particular case, we are talking about a result which was a cure, which in this sentence is used to describe what happened with the study that was carried out and in which Aunt Helend decided to participate. This is why the correct answer is C: Study, because the clause: resulted in a cure, is further explaining what happened with the study the woman embarked in.