Final answer:
The yellow triangle sign with a child running after a ball signals 'Caution: Children at Play', alerting drivers to be careful of potential children in the area.
Step-by-step explanation:
The yellow triangle sign with a child running after a ball typically indicates 'Caution: Children at Play'. This sign is used to alert drivers to slow down and exercise caution because there may be children playing nearby. It is not an indication for 'No Ball Games Allowed', 'School Zone Ahead', or 'Playground Closed'. Instead, it serves as a warning to be vigilant as children may unexpectedly enter the road, often in residential or park areas where children are known to play.