Which vehicles should be prepared to move to another lane to allow faster traffic to pass?

• Vehicles in the right lane used for slower traffic.
• Vehicles in the left lane.
• Vehicles in any lane except the right lane used for slower traffic.
  Explanation:

  "Vehicles in any lane, except the right lane used for slower traffic, should be prepared to move to another lane to allow faster traffic to pass."
• Vehicles in the middle lane.