What does this sign mean?

• These signs tell you to look, listen, and reduce speed because you may have to stop for a train.
  Explanation:

  "These signs tell you to look, listen, and reduce speed because you may have to stop for a train."
• These signs tell you to keep going at the speed you are already driving.
• These signs tell you that there are no trains on the crossing.
• None of the above.