When driving in a residential area, what is the maximum speed limit?

Answer: D — 25 mph

The maximum speed limit when driving in a residential area is typically 25 mph. This is because residential areas are often populated by pedestrians, children playing, and various obstacles, making it dangerous to drive at a higher speed. Option A and B are incorrect because 10 mph and 15 mph are extremely slow and would not be practical for navigating through a residential area. Option C is incorrect because while 20 mph may seem like a reasonable speed, it is still too fast for a residential area. 25 mph is the standard speed limit in most residential areas and it allows for a balance between safety and practicality.