Which of the following increases the risk of hydroplaning?

The option highlighting heavy rain and worn tires is correct because it emphasizes two critical conditions that significantly contribute to the risk of hydroplaning. When it's raining heavily, water accumulates on the roadway, creating a layer between the tires and the road surface. This becomes particularly dangerous if the tires are worn, as they are less able to channel the water away from the tire's contact patch with the road. Worn tires have reduced tread depth, which diminishes their ability to grip the road effectively. This combination of heavy precipitation and inadequate tire performance results in an increased likelihood of losing contact with the road, leading to hydroplaning.

In contrast, deep treads on tires are designed to improve water displacement and enhance grip on wet surfaces, which reduces the risk of hydroplaning. Properly inflated tires also play a critical role in maintaining optimal contact with the road, further lessening hydroplaning risks. Driving at high speeds can increase the chance of hydroplaning as well, but it is the specific combination of heavy rain and the condition of the tires that most directly heightens the risk.