Vending machines, because each is just a word telling you that both were empty. Vending machines is what the whole sentence is based on.
I guess that it’s false because it’s showing in the passage
The answer is D. The author supplies a rebuttal that quotes more current research. He quotes two sources, an article from 2009 that argues that cell phones cause too many distractions (the counterclaim that he wishes to disprove) and a poll from 2013 that reveals that 67% of high school instructors now encourage students to use phones in the classroom setting. The second source serves as a counterpoint to the first, since it shows that high school instructors now view phones as a teaching aid instead of a source of distraction.
