Final answer:
The white railroad crossing sign means that drivers should look, listen, and prepare to stop at the crossing if necessary, emphasizing caution and safety near train tracks.
Step-by-step explanation:
The question is asking for the meaning of a white railroad crossing sign. The correct response to the meaning of this sign is 'c. Look, listen, and prepare to stop at the crossing, if necessary.' This advice is crucial for driver safety as it indicates that there may be an upcoming train, and even if there isn't an active signal or barrier, drivers should proceed with caution, looking and listening for any signs of an oncoming train and being ready to stop. Traffic signals play a significant role in ensuring pedestrian safety and vehicular control. At railroad crossings, they are particularly important as they regulate the flow of traffic to prevent accidents with trains, hence why the advised action is to look, listen, and be prepared to stop.