Am much obliged to get the opportunity of helping you in your question, thank you for this chance!
the possible answer to this question is;
C. Difficult refocusing your vision.
This is because, for instance, when using a cell phone while driving, all your attention may be drawn to the phone and it might be difficult to maintain your focus on the road hence losing your proper vision to other coming vehicles. Lose of vision while on the road may cause fatal accident.
Please let me know if you need any clarification. I'm always happy to answer your questions.
Oct 5th, 2015
hello, in case you need further clarification, please, feel free to engage me.