What does the solid yellow signal indicate?

• Pedestrians have crossed the street, so drivers may proceed with caution.
• There are pedestrians within the crosswalk.
• There are pedestrians on the sidewalk to cross the street.
• Pedestrians are preparing to cross the street. Drivers must reduce their speed and prepare to stop.
  Explanation:

  "This solid yellow light serves as a warning for drivers, alerting them to reduce their speed and prepare to stop as pedestrians are preparing to cross the street."