What is the correct interpretation of a driver extending their arm straight out the window?

Answer: B — They are turning left

When a driver extends their arm straight out the window, it serves as a hand signal to indicate a left turn. This method of signaling is important for communicating intentions to other drivers and pedestrians, especially in situations where the vehicle’s turn signals may not be visible or functional. Using hand signals is a traditional and effective practice that enhances safety on the road. In contrast, other options such as stopping would typically be signaled with an arm angled downward, a right turn is indicated by an arm bent upward, and a U-turn is not commonly signaled in the same manner as turning left. Thus, extending the arm straight out is universally recognized as the indication of a left turn.