题目选项分析

Guitar strings often go "dead"—become less responsive and bright in tone—after a few weeks of intense use. A researcher whose son is a classical guitarist hypothesized that dirt and oil, rather than changes in the material properties of the string, were responsible.

Which of the following investigations is most likely to yield significant information that would help evaluate the researcher's hypothesis?

【选项】Determining whether smearing various substances on new guitar strings causes them to go dead