During a vehicle inspection, what indicates that the windshield wipers are functioning properly?

The functioning of windshield wipers is essential for visibility and safety while driving, particularly in adverse weather conditions. When evaluating whether the windshield wiper system is working properly, it is important to consider both the operation of the wipers and the washer fluid system.

The correct choice highlights that both the windshield wipers and the washer fluid operate normally. This dual functionality ensures that not only do the wipers clear rain, snow, or debris effectively, but also that the washer fluid can supplement this action by cleaning the windshield when necessary. The interplay of these two components contributes to optimal visibility. If either the wipers or the washer fluid were malfunctioning, it could severely impair the driver's ability to see, especially when the windshield gets dirty or obscured.

While the other options focus on individual aspects of the wiper system, they do not fully encompass the complete functionality required for effective operation. For instance, a wiper may not leave streaks or operate quietly, but if the washer fluid is ineffective, this indicates an incomplete assessment of the system. Hence, the comprehensive evaluation of both aspects validates why the choice that encompasses both the wipers and washer fluid functioning together is the best indicator of a properly operating windshield wiper system.