题目选项分析

Educator: Despite claims that books offer a better reading experience than electronic readers, a recent study found 90% of subjects demonstrated an increased ability to recall facts when that material was presented on an electronic reader rather than on the printed page. Therefore, if the reader hopes to have a deeper understanding of the material he or she is reading, that person should study using an electronic reader.

Which of the following calls into question the conclusion of the educator?

【选项】Amongst adults, electronic readers are quickly displacing books as the preferred medium for reading.