Final answer:
A hand signal with the driver's hand and arm straight out indicates a left-turn.
Step-by-step explanation:
When a driver's hand and arm is straight out, it is a hand signal for a left-turn. This signal indicates to other drivers that the driver is planning to make a left turn at the upcoming intersection or roadway.
For example, if a driver extends their left arm straight out of the vehicle's window, it is a clear indication that the driver intends to turn left. Other drivers who see this signal should be prepared to yield to the turning vehicle and proceed with caution.