The writer wants the tone of sentence 13 (reproduced below) to convey the emotional turmoil experienced by people who participated in the experiment.

Many subjects did not turn Nao off or were unsure whether to do so.

Which of the following versions of the underlined text best accomplishes this goal?

A. (as it is now)

B. thought turning Nao off might be wrong, and some did not do it

C. found the question of whether to turn Nao off a bit troubling

D. considered not turning Nao off or even failed to do it

E. refused to turn Nao off or struggled with the decision