Why should you not use a cellular phone while fuelling?

• You might not see if the fuel is up to the mark or not.
• Sometimes, phones that light up while ringing may have enough energy to provide a spark and ignite the gasoline vapours.
  Explanation:

  "Do not use a cellular phone while fuelling. Phones that light up when switched on or when they ring may have enough energy to provide a spark. The spark could ignite gasoline vapours."
• The phone might cause a distraction.
• None of the above.