Why should you not smoke, light matches, or use a lighter when fuelling your vehicle?

• Gasoline vapours mix with air, which contains oxygen.
• If you add an ignition source such as cigarettes or matches, a fire or explosion can occur.
• Nothing happens.
• Both A and B.
  Explanation:

  "Do not smoke, light matches or use a lighter when fuelling your vehicle. Gasoline vapours mix with air, which contains oxygen. If you add an ignition source such as cigarettes or matches, a fire or explosion can occur."