How should you inform approaching drivers that there has been a collision and people are injured?

• Turn on the emergency flashers
• Set up warning signals and flares
• Ask someone to warn the approaching drivers
• All of the above
  Explanation:

  "In case of a collision with injuries: (1) Turn off all engines and turn on emergency flashers; (2) Set up warning signals or flares to alert other drivers; (3) If possible, have someone warn approaching drivers to reduce the risk of further accidents."